I took the time to import the project into Unity, but it's hardly playable:
- The FPS controls don't actually work as the gun stays fixed in a certain direction
- The vertical rotation is slow and inverted
- The gun can't be used to shoot
- Enemies and stuff just stand still
- Jumping is floaty
- There's no clear goal
Better luck next time! Be sure to read up on how to publish a game with Unity, it's actually quite simple.