The core gameplay works, but I think the main issue is with the game feel
- There is no walking animation, so it feels like your character is sliding/hovering over the ground.
- There is no death animation. You shoot an enemy, it magically disappears, a (nice) particle effect appears and then a corpse magically appears.
- I encourage you to see this conference from the designer of Vlambeer. It is called the Art of Screenshake and it talks precisely about game feel.