Original idea! I love the beginning starting with the instructions written in large, so there is no need for a tutorial - great design :)
The controls felt super fluid, I liked them a lot.
The mechanic is interesting - although the gun moving in random directions means there is no 'strategy' to shooting. If the gun had more predictable movement (but was still outside the player's control), then it could lead to some interesting strategies to take out the beer enemies.
I like the option for big bullets, but I'm not sure what the lock direction button does...?
The screen shake and bullet noise sfx were very cool.
I wasn't sure of the aim of the game so after a while it just felt like I was wandering around aimlessly - this felt repetitive. Different enemy types would help it feel less repetitive too.