Some of the graffiti was extremely hard and I never knew if I was actually making any progress on each individual piece. It also gave little incentive to rush. I'd recommend making a version where you have 30 seconds and gain time by damaging graffiti to encourage players rushing through the way you intend. Also the backing music choice was interesting
EDIT: to clarify I love the sound design, animation, and graphics, so you did a lot right, it's just easier to comment on negatives of course.