Very short but really great retro combat platformer like Shovel Knight. A game this good has no business being free! I would have been happy to have paid around $7-10 even with it being as short as it is. If it was a full-length game with some of the (very few) kinks ironed out I'd happily do $20.

Great (but limited) music
Really fun level design
Good upgrades
Very humorous writing

Very possibly the best truly free game I've ever played.
I'm talking a lot about the price but the rating is not informed by that hardly at all. It really just lacks a bit of polish which I forgive because of the likely non-existent budget. Other than that this is just a really solid game.
Why are you reading this review? Go download it!