Is 'ART IS RIFLE' colorblind-friendly?

Yes! When I was designing the levels, I always kept this in mind: one of my design principles was that the levels must be solvable without relying on colors. The reason for this is a visual mode that will be unlocked in PLAY+. One of these modes allows you to play the game without colors! In that mode, you can only rely on sound and animation cues to solve puzzles. Some of my tester friends even completed the game that way on their first playthrough.