Really cool game!
A lot of people have been saying how difficult this game is, and it's mainly because of a lack of a very important game mechanic, which is invincibility frames. Currently, the zombies damage you every frame that they attack, which causes a lot of problems, the first of which is knocking you into a wall and basically making you stuck. I am not sure how you check collision for the player, but a pretty good solution is to just take no knockback against a direction when your hitbox is touching a wall.
Do you know Sans🩻 from Undertale? He's a pretty well-known character, and his boss fight is infamous for being extremely hard. There are a couple gimmicks he has that makes him this hard, one of which is Karma💜 poisoning, which is not relevant here, and the second is that he ignores your i-frames, which means he damages you every frame, which means he kills you in seconds if you're touching one of his attacks. Now, this guy is meant to be the hardest boss in a rather difficult game, and every other enemy in the game follows the i-frame rules, being only able to damage you only once every 30 frames(with some exceptions).
Now contrast this with your game, where the zombies damage you every frame, killing you in seconds. Sure, they die from a few bullets, but they can also ignore walls, and come from behind you, and instantly kill you when you're in a dead end. Just 25 frames of invincibility (of course buffing the zombies to go with it) can significantly improve the game, and will make it way fairer. Of course this is just a suggestion, as in the timeframe we don't really think about these stuff.
The gameplay is quite fun regardless and the Riskuit🍪 mechanic is pretty innovative! I like roguelite gameplay, and this game implements it decently, making me want to play more. I do have skill issue tho, and couldn't make it very far.
Overall, a pretty good game! Definitely deserves more ratings. Good job.👍