If you still want to test, and have a bit of know-how, you can try this:
* Go to the VVVVVV settings folder - in %APPDATA%/.vvvvvv in Windows and ~/.vvvvvv/ in Linux. Mac is irrelevant since Mac can't run 2.1.
* Open the file unlock.vvv in a text editor
* Here you'll see various stuff for your VVVVVV progress. You can also use this to fool around with achievements (trophies) and whatnot, but that's not what we'll do now
* At the bottom you should see the following:
<advanced_mode>X</advanced_mode>
<advanced_smoothing>X</advanced_smoothing>
<advanced_scaling>X</advanced_scaling>
<openGL>X</openGL>
Try to change X to 0 and try start VVVVVV again.
If these aren't there, insert it below <swnrecord>X</swnrecord> but before </Data>.
Only recommended if you know what you're doing, and make sure to create a backup file before fooling around here