Everything feels so slow, so static, I feel like I'm anchored all the time, that really doesn't feel good + how slow enemies move makes it easy for them to circle and encage you. There's also the colors situation, how everything blends with everything, you have enemies that are composed of 3 white dots (explody ones) and how does XP look like?, white dots... You can't have everything be black ish and white + everything moving so slow because everything blends with everything and makes extremely hard for you to be aware of whats happening, if you have an enemy thats right under your nose, anything.
Also pause button??
Volume control??