It's fun but too easy, especially when you realize the grenades are infinite, don't hurt you, and can be rapid-fired at close range. Anything in your way is shredded if you hold fire and keep right clicking, especially the bosses.
Also I'm sure it's just from being so early in development but not even a "You Win" screen? I was confused when the level after Krampus had the tutorial signs.
A bug I noticed: if you shoot or lob a grenade at Krampus before the cutscene, he turns in place for his animation. Looking forward to continued development!