I won’t mention the small screen, cause it already has been.
Some aspects of gameplay were good, moving with the keyboard and aiming/shooting with the mouse felt good.
However, some aspects felt a bit frustrating.
- Jumping between gaps (if you aren’t on the ledge you can’t jump, however some games give you a little forgiveness; see Tip 4).
- At one point I got stuck under a platform and couldn’t move. Maybe shrink the collision box of the player a bit.
Just some suggestions.