Nuclear Throne

[Toffee.]

This game is crazy as hell, and can be quite rage inducing. But oh my gosh it is so much fun, mostly because of how wild/insane it is.
They give you a handful of characters to use, all of which have their own unique abilities/etc.
You can use many different weapons to blow up everything in your path/etc.
And you can even upgrade your character along the way.

The trick, however, is that if you die.... Then your back to the beginning. But that's the point, because everything is randomly generated in this game, so every run/etc is bound to be different from the last.
The main premise of this game is the fact it's a bullet hell/etc, but they ease you into it so your more used to the clusterfux of bullets/etc later on.
The game has a handful of stages, but they get crazy REALLY fast.
All in all, it's a fun game.

It's also like 13$ on Steam.