Fun game, and it gets super hard the deeper you go. The way you unlock new color schemes as well, made me play more than I should have.
It gets harder in later stages because you don't know where the next bomb is going to drop. This is manageable in the early parts, but later on if you in the direction of a low dropping bomb, it's game over. An arc of where the next bomb will drop might be nice, but that is just my own opinion.