The choice to constrain movement to a 5x4 grid is clever, especially in what otherwise resembles a vertical shmup. Simplifies the mechanics without losing anything important for this game.
Really good gameplay - my only complaint is that the difficulty gets a bit rough in the end given how long it takes to get there. Aesthetics are also on point - the plain white orbs feel slightly out of place, but this would be a trivial thing to improve.