Simple and nice use of the theme but I'm able to hold in one direction and keep attacking since there is not attack cooldown. You combat this with the red squares that fall in the next level but there should definitely be a cooldown for the attack state when moving. Maybe you need to stop and move again to attack after the cooldown finishes or maybe it triggers again if you're still moving when the attack is in cooldown.
I like how the progress of attacking enemies also doubles as your health. Visuals are crude but understandable for a game-jam game. Cool, simple mechanic!