Didn't ever play this genre, have to say that was pretty fun, around night 5 I felt like that's too easy and repetitive and I almost quit, but decided to try few more nights, and then I got my ass handed to me by night 10 xD.
I think this game can be really addictive if polished and taken to a good direction, I loved the art and the monster theme, few minor things that bothered me:
1. I feel like there isn't enough indication to the user that a drink was served, there is a "sliding cup" sound but it very faint and when you place two drinks really quick the sound is played once, so I think there should be a more noticeable sfx maybe so lines for the monsters like "its about time" or something like that, and a better visual indication then the progress bar changing color and resetting
2. the progress bars color blend too well with the red color of the bar and its quite easy to miss or think you have red bars when you don't have them, maybe an outline to the bars?
3. I wish I had another way to survive then rely only on choosing the attack damage or the health damage upgrade, meaning I wish there was a place to use my skills as a player somehow
overall very polished, fun and addictive, a lot of potential definitely a top contender :)