Loved it! Beautiful aesthetic—though it was a bit too dark. I had to increase my screen brightness to see everything clearly.
The guards have a cool design and follow predictable patterns if you're patient, which works well. The only frustrating part was occasionally being killed by a guard right at the start of a level. Maybe consider having them avoid the player’s spawn point?
Also, if you're interested in adding an online leaderboard, you could easily do it with LootLocker for free! (I don’t have any stake in it, I promise.)
Great job overall—GG!