IMO, there's too few checkpoints. Other than that, the level was pretty fun for a first try!
1: Intended map leaving possibility (as in the last part of the level) is like asking for major bugs. IMO, you should prevent this.
2: In Lines Onwards, you can get too low on the lower gravity line when going to the next room, making it possible to skip the entire level after that.
3: The ceiling between the rooms "RipOff" and "Blue and Trouble" is 1 pixel off (the ceiling in Blue and Trouble is a pixel to low).