It’s an amazing game and addicting once you get into it. If you think Quake and Devil May Cry sounds like a fun combo, this is the game.

Just be aware the game isn’t finished yet. The last few levels are missing.

In all honesty, it's a great game and it's not that expensive. There's currently even a deal in the Humble Store: https://isthereanydeal.com/game/ultrakill/info/

And in case you liked it, Turbo Overkill is similar and also great.

I just bought it based on this alone. Early-access and FPS games aren't typically my thing, but I like the cut of this person's jib.