I played this yesterday but neglected to leave a comment because I was tired out of my mind when I did. This is a very interesting example of how a simple gameplay loop can make for a really fun gameplay experience.
The graphics I could give or take. The color palette goes for the classic Gameboy look, but the high resolution makes it look off. The music is quite great, though, and I love how it gets more intense the closer you are to the end of a level.
The simple and effective gameplay is where this one shines. As a strong guy on top of a tower, you must keep a bunch of monsters from climbing to the top by throwing barrels at them to kill them. The monsters can climb ladders, and some monsters behave differently from others. There are monsters that randomly choose whether they'll climb, others that always climb, and others that don't climb at all, and it makes for a really intense and fun gameplay experience.
If I were to change some things, I'd remove the player character's collision with the barrels. I don't see what purpose that serves other than being obnoxious. Also, maybe making it so that one barrel can't destroy the other, so that we don't end up short on ammunition when we need it the most.