Sometimes I got shoot when almost entering the screen so I decided to move slower and fire as soon as I see something or to move back quickly and return slowly, I don't know if that was the idea or not but in someway I enjoyed doing that fire quickly move, it felt cowboy (at least thinking in the movies), I liked the fire first, think later move.
Also, when killing enemies, the feedback was a bit confusing, the start blinking like they are temporary invulnerable or something, maybe it would've been better to make a different pose or make them explode, the first time I shoot at them and thought they were still alive so I moved back and then returned and they are not there. I am even able to fire multiple times to a blinking (already killed) enemy.
There was an enemy with a knife (I suppose) that was hitting me multiple times and I didn't notice (I believe it only happens with that enemy).
Anyways, it was fun to play, great work.