Lovely drawings, animations and sounds, plus it was very easy to get started!
I lost pretty quickly on my first game, and enemies never showed up when the game restarted afterwards. But I reloaded the page, and managed to keep Olaf safe on my second attempt!
Once you identify and understand the two types of enemies, it gets pretty easy... but not so easy that I didn't have to focus - I was still alert and on edge for the entire ~60s game!
One thing I noticed is that the music stopped a little bit before I finished the game, so it would've been nice to extend it a bit or make it loop. But otherwise, it's a nice, simple and fun game!