I didn't play it much longer than a minute, but I did test a few things out that I'll run by you. I'll start by saying some or all of this may have been completely intentional, but as you didn't mention it in your original post, I'll comment on it.
Holding 'Q' makes the player move left at high speed with no animation. Likewise, 'D' does the same thing in the right direction, 'S' in the down direction, and 'Z' in the up direction. The sprites change to the appropriate facing base sprite when the keys are pressed, so for that reason I felt like it may have been for debugging purposes to quickly check if the different areas were being loaded correctly.
Also, when firing the projectiles, I can hold down the button and it will fire continuously. This also works while moving in any direction. If I am holding the UP key while firing projectiles, and then begin holding the RIGHT key so that I'm moving in the North-East direction, the projectiles continue firing. However, if I begin by moving North-East while firing continuously, it will stop firing if I take a finger off of one of the movement keys (say I let go of the RIGHT key but keep holding the UP key, so I go from moving North-East to just North).
If the last one is a feature, it's kind of odd, but I'm almost certain something there is a bug. I hope it was at least understandable.
Small edit: Apparently, the projectiles will stop firing regardless of what key is pressed, even if the additionally pressed key has no function.
