Today is the 10th anniversary of VVVVVV’s release!

Or possibly tomorrow is, depending on who you ask – technically, the game first went live at 3am GMT on the 11th January 2010, after a very, very long day of fixing every last bug I could, making last minute builds, and trying to slowly upload everything on an extremely unreliable internet connection that kept cutting out. But I’ve always gone by “it’s not tomorrow until you wake up” rules, so I still think of January the 10th as the real launch day <3

Gosh, ten years.

VVVVVV is such an important game to me, I barely even know where to start. I wanted to do something special to mark the occasion: so, as of today, I’m releasing the game’s source code!

[VVVVVV Source Code on github]

The repo contains two versions – the desktop version, ported to C++ by Simon Roth in 2011, and later updated and maintained by Ethan Lee – and the mobile version, written in Actionscript for Adobe AIR, based on the original v1.0 flash version of the game.

I wanna give a big big thank you to Ethan Lee, who helped a lot to prepare for this, including getting the repo ready for the public, and organising the reveal on AGDQ (hi speedrunners!)! Thanks Ethan!

A quick overview of the source code

So, I think a fair question to ask here is: “What’s interesting about the VVVVVV source code?”.

I think even a peek of the source code will quickly reveal that VVVVVV is not a technically sophisticated game! Even by the standards of self taught indie devs, it’s kind of a mess.

Some possibly interesting notes/explanations of why things are they way they are:

  • There’s a lot of weird stuff in the C++ version that only really makes sense when you remember that this was made in flash first, and directly ported, warts and all. For example, maybe my worst programming habit is declaring temporary variables like i, j and k as members of each class, so that I didn’t have to declare them inside functions (which is annoying to do in flash for boring reasons). This led to some nasty and difficult to track down bugs, to say the least. In entity collision in particular, several functions will share the same i variable. Infinite loops are possible.
  • If you’re looking for the game’s text, that’s mainly (but not entirely) in the Scripts.cpp and TerminalScripts.cpp classes. These functions basically load data into a very simple script parser that controls cutscene logic. Fun fact: modders reverse engineered this “internal scripting” years later to do amazing things with custom levels that I didn’t even know were possible.
  • Somewhere along the road, I picked up that it was a good habit to separate your code into input, logic and render, and boy did I take that to heart. Most of the critical game code is in three files – input.ccp, logic.cpp, and the incorrectly named titlerender.cpp. Every state in the game is packed into these three files, under functions called things like “teleporterrender” and “towerlogic“. There’s a lot of copy and pasting going on here.
  • All the actual levels in the game are hardcoded in huge arrays that I generated with my own map editor, which exports the levels in source code that I could read in. This is just kind of how it worked when making a flash game in 2009 – accessing external data assets is hard to do, so it just made sense at the time to compile that into the game instead. All the really big files (like Spacestation2.cpp, Finalclass.cpp and so on) were made this way. I’ve uploaded the code for the editor here for completeness, but it’s not really useable anymore to be honest (it requires Allegro and Mingw to compile). I made a similar tool for rearranging the final level layouts!
  • When I was making this, I didn’t really understand how static classes worked, or why they were a good idea. I think I read somewhere that static classes and global variables were BAD in flash, so I tried to avoid using them at all ever. The result? Virtually every function in the game is passing around the following arguments: “Graphics& dwgfx, Game& game, mapclass& map, entityclass& obj, UtilityClass& help”.
  • VVVVVV basically has no temporary objects, and it fills all of its entity arrays (and most of its other data arrays) with hundreds of blank entries when the game is first initialised. It does this because I read somewhere that deleting objects in flash causes weird hiccups as the garbage collector takes over and slows things down, which is actually sort of true. I was still doing this weird thing in new projects until very recently – I finally broke the habit in Dicey Dungeons.
  • One more: as well as the cutscene parser, I had another way to control game logic as you were playing – a monolithic state machine, which had gotten completely out of control by the end of the project! You can find it in Game::updatestate, and I kinda recommend checking this out even if you don’t read anything else! This controls things like triggering the start of more complicated cutscenes, where teleporters send you, the timing of the level completion animation, and other miscellaneous things that I just wanted to kludge in quickly. The states are numbered, and it counts all the way up to 4099, with gaps. When I was developing the game, I kept a notepad nearby with the important numbers written down – 1,000 triggers the collection of a shiny trinket, 3,040 triggers one particular level completion, 3,500 triggers the ending. This dumb system is the underlying cause of this amazing 50.2 second any% speedrun of the game.

I dunno, what can I say? I was young and more interested in getting something on the screen than implementing it properly. Maybe the best thing about VVVVVV’s source code is that is stands as proof of what you can hack together even if you’re not much of a programmer.

Looking back through it myself all these years later, I find it really funny how much of it is basically just the same parts copy and pasted over and over, with the values changed. This basically makes it impossible to read and maintain ten years later, but back when I was in the thick of it, it made it really fast to iterate and add new things. I’ve gained better habits over the past decade, and I’m definitely a better programmer now – but it does seem to take me longer to do things.

Surprise Birthday Party!

Just as I was getting ready to post all this, Sergio Cornaga announced a 10th anniversary game jam for VVVVVV over on glorious trainwrecks!

VVVVVV’s 10th birthday eVVVVVVent!

I am so excited about this, haha – and I love glorious trainwrecks, which hosted the regular Klik of the Month jams that I did regularly around the time I was making VVVVVV. This feels like a perfect home for it!

I’m really, really excited to see what people come up with – once the jam ends, I’ll do a big round up post here on this blog, in the style of the old VVVVVV player level posts I used to write <3

Even before I released the game’s source code, I made the tools to make and play VVVVVV levels available for free in the “Make and Play” edition back in 2014! You can download that from here! If you’re interested in making levels in the VVVVVV editor, this thread is a good place to start! Good luck!

Mushy stuff

Ahhhhh so I’ve talked about how I feel about VVVVVV a little before – just before the first anniversary, I posted about how things were going for me when the game first came out, and how its success changed my life. Then on its firth anniversary, I posted about how VVVVVV felt like a once in a lifetime project – that nothing before or after could come close to.

A decade on, I still feel the same way. I’m incredibly proud of VVVVVV, and grateful for everything. I want to thank everyone who helped me along the way – Magnus for his incredible soundtrack, Ethan and Simon for all their work to bring the game to more people, Bennett for naming the rooms, Stephen for helping me get that mac build out late in launch day. This game is special to me – thank you to everyone who played it and supported me over the past ten years. It’s meant so much. <3

43 thoughts on “VVVVVV’s source code is now public, 10 year anniversary jam happening now!”
  1. This game is delightful – gave me such manic miner vibes. Your other games are top notch too (love Super Hexagon especially). So nice to see unusual indie games that do well.

  2. While this is definitely really cool, I would like to ask you to please not call it “Open Source” as the license used does not fit the Open Source Definition (, point 1 for example). Would you consider renaming the blog post to something like “vvvvvv’s source code is now publicly available” or the likes?

    I’m not going to ask you to change the license or anything, you do you, it’s already really cool you shared this in the first place! I just like it when words are used with their intended meanings 🙂

    Also, I guess I really got to finally try this game out. I loved Celeste so more “twitch platforming” would definitely be interesting!

  3. D’awwwwww we love you Terry! What an awesome way to mark the milestone! My jaw dropped when the reveal on AGDQ happened – this little C64-em-up has inspired so much in the indie sphere over the years. Can’t wait to see what the next decade brings for you!

  4. “Open source” is not reserved for exclusive OSD use. Nor does their definition of it make any sense to the laymen to begin with. “Open” is “accessible”, not “libre”.

    Squatting a term and advising others to use made-up goofy terms like “shared source” that make even less sense is plain silly. The only thing this does is it turns people against OSD, because this attitude comes across as gatekeeping and zealotry.

  5. @GatekeepNot The idea that a phrase should have a clear and well-defined meaning is not zealotry or gate-keeping. As-is, the source code is not accessible to those who would like to make money from selling mods. So it’s not open source. It still is useful, just only to modders who can afford to give their stuff away for free.

  6. Wow! this is so cool! i can finally put my outdated action script skills to use. VVVVVV is one of my favorite games so thank you for making it!

  7. @anonymous
    The code is accessible to everyone; therefore, it’s reasonable to call it “open”. Just because someone isn’t allowed to sell mods based on it doesn’t make it inaccessible to them- they’re allowed to look at it the same as everyone else.

    The only thing that “open source” necessarily implies is “anyone who wants to access the source code can do so”. Anything else (redistributing it, modifying it, selling it) is a detail decided by the specific license.

    @GatekeepNot said it perfectly- “open” == “accessible”.

  8. LOL

    first we have

    “declaring temporary variables like i, j and k as members of each class, so that I didn’t have to declare them inside functions ”


    “i read … global variables were BAD”

  9. @also_anonymous No, it is not reasonable to call it open. The license is discriminatory towards modders. A professional modder needs to be able to work on the code and recoup some expenses from that work. That is not allowed by this license. The code is a piece of engineering, it’s not equivalent to literature where you read it and then you’re done. Only half of its usefulness is in being able to read it. Open source communities have been through these discussions so many times that it’s tired by now. Discriminating against certain business activity is not a way to build an open and welcoming community.

  10. Guys. He changed the wording without argument and thanked the commenter for the revision. He’s not claiming the ‘open source’ label and didn’t intend to, and he’s being clear about his terms now. This is not the place for a semantics argument that is old and ongoing and won’t be resolved today. Let’s let a good thing be good, yeah?

  11. please tell me you’ve learned about std::vector::resize() and reserve() in the meantime, there’s a lot of needless reallocation/resizing going on, and for most points (where the array is filled with empty/default objects) a simple resize would have sufficed

  12. Thank you for everything. I still play Super Hexagon and VVVVVV to this day, and even Don’t Look Back, just last week.

    I wish you nothing but further success and happiness. <3

  13. @Eric This is not about semantics. It is clear from the license who is allowed to profit from this and who isn’t. The game’s community is large, its members have money, and they are willing to spend it. The money will not disappear from the community as a result. It will just find somewhere else to change hands. The announcement of this at AGDQ makes the intent very obvious. Speedrunners, streamers, conferences, e-sports events, Twitch, etc, are all allowed and encouraged to make money off of use of this code, and they will continue to do so. Now the authors allowed modders to look, and make modifications, and they allowed them to send their modifications to those speedrunners and streamers so they can, in turn, make money off of playing them. But if the modder dares to ask for a dollar for any of this, then they get hurt.

  14. Are you going to eventually release the source code for the other platforms the game was released on? I am most interested in seeing the 3DS version of the game.

  15. I have a lot of respect for you for being a MAN and releasing the source code knowing that a bunch of boring nerds who’ve never accomplished anything themselves would take pot shots at it.

    You’ve immortalized your game and made sure that’ll be ported to every toaster on the planet, and like you said, in the end, all that really matters is that it works and provides value to people.

    “Good” code is overrated. If you actually look at almost any substantial project, they all turn into shit by the time they ship anyway.

  16. Would it be possible for you to reconsider your license to something such as the CNPL license as summarised here:
    It would be less commercially restrictive to modders while still preventing abuse by a corporation.

    Aside from that, this is pretty great and could potentially inspire some people to learn how code works.

  17. This is awesome! Thank you for doing this. Way too many great games are lost precisely because of the lack of source.

    I know it’s a lot to ask, but please reconsider the license choice! There are many fsf/osi approved licenses that allow you to both retain the rights on the vvvvvv name and prevent exploitation of your work, while still giving freedom to the users and ensuring that your work will live on!
    In particular take a look at the GPLv3.

    Relevant links:

    And thanks again a lot! Can’t wait to get to tinker with the source!

  18. > You may not alter or redistribute this software in any manner that is primarily intended for or directed toward commercial advantage or private monetary compensation.


  19. The CNPL license would still not make this open source or free software. The license is discriminatory against who can use the software.

  20. I remember first seeing the game when I was 9 years old a decade ago on Kongregate. This was one of my favorite games and I played it a lot over the years even on humble and steam. Great to see you putting it out there!

  21. > The CNPL license would still not make this open source or free software. The license is discriminatory against who can use the software.

    Calling software “Free” is misleading if it can be used to restrict the freedom of others, as clearly explained in the description of NPL/CNPL, and if you prioritise software “freedoms” over human freedom, you’re straight up a terrible person as there’s absolutely no moral justification for such a position.

    Technology exists to further humanity, and as such, all licenses should be subject to moral scrutiny. The GPL and other so card “free software” licenses have failed to protect the very thing they claim to protect, freedom.

    Too much of any one freedom ends up being a bad thing, or as an old saying goes “Your freedom to swing your fist ends just where my nose begins”

  22. Takes a lot of guts to let your early work get picked apart by the whole Internet. Nice!

    Also: sorry for the open-source-license-pillowfight crowd. Your license is fine, it reads very similar to Creative Commons Non-Commercial, and there’s nothing wrong with that.

  23. Thanks for releasing this! It’s already been ported to Haiku 🙂

    Also sorry the open-source-license-pillowfight crowd 🙂 You do you.

  24. Good job on the game Terry, I wonder what the future holds for this game and its wonderful community! Outlook: Positive


  25. I remember VVVVVV along with the likes of Super Meat Boy and Braid as being part of the first generation of indie games that took indie gaming from obscure freeware titles you only found on the internet if you looked hard enough to the mainstream landscape. You and VVVVVV are a significant part of modern gaming history. Thank you Terry for your fantastic game and for the games you paved the way for, and thank you SoulEye for your music that I still listen to today.

  26. I was confused when I saw a basic thing that had almost everything except for one required file to run it when I was looking at the configure section of RetroPie. Now I know why I saw it and it shows signs of being able to play the make & play edition of it.

  27. First of all, I would like to thank Terry for making the source code of your game available. Few developers are willing to that anymore. It allows people to play games in ways they were never designed (my favorite example being the port of Doom I can play on my music player). Hopefully you also get help in return in the way of bug fixes!

    As for anonymous from January 11th and 14th, the CNPL/NPL is a complete joke of a license. “Violence” is so vaguely defined that it can be applied to practically any use of a work and would render it usable by no one. Who would want to use a work with the constant fear that they may violate the terms in some way? That isn’t freedom. If you believe the only people at risk of violating the terms of the license are groups intending to abuse people, you are mistaken. Interestingly, the people advocating for such a license would likely be the same people violating its terms. Just look at the current state of social media. People frequently threaten and torment others, believing their stance is justified, but using the software for that purpose would be a blatant violation of the CNPL/NPL unless the software authors unfairly turned a blind eye to certain violations.

    Also, people can have multiple priorities. You can advocate for software freedom and human rights. The two are not mutually exclusive. While the CNPL/NPL sounds like a good idea on paper (and in an ideal world would be an excellent solution to preventing the misuse of software to violate people’s human rights), in practice it is doomed to failure.

  28. Hello Mr. Cavanagh,I have been a big fan of Dicey Dungeons since around v0.4, and have anticipated every build since.  Congrats on all the success that your hard work has accomplished, building such a great game and such a fine team.  I only really played console games, card games, D’n’D back in the day, and somehow I came across your game dev early and was hooked.  Yours was the first game I bought on line.  I really like how it has turned out and played it deeply on itch, but that being said, I LOVED versions 0.7 to 0.9, and regularly went back to them, just for the FLAVOUR.  I really enjoyed the aesthetics of those early versions, so it was with a heavy heart that I found them inaccessible on your site.  I guess all things must end (remember that dicey encyclopedia? I do!), but I was wondering if those early builds are gone forever or if I can still occasionally get my kicks playing the thief in v0.9 at another address?  Those pixelated characters are burned into my brain, and I just wanted to drop you a line to say thank you for the good times.Best wishes from Nova Scotia! 

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.