One of the most fast-paced shooter i have played. The weapons and enemies allow for an absurd amount of possibilities of things you can do to kill demons and still your thirst for blood. The level design is amazing: compact enough to allow for speedruns but with so many details hidden for you in plane sight to make them feel really complex at best. Even some secrets that you are not prepared for...

The game does not feature much story in the traditional sense, but when it appears it is stuck in your head for days.

And the soundtrack.... ♥♥♥♥♥♥♥♥♥. It is perfect. It is EXACTLY what it needs to be to either give you full adrenaline pumps or take you back down to earth in preparation for the next fight. A fest for your ears if you like metal. breakcore or similar music.

Going in, expect a (sometimes overstimulating) doom-like with ps1 graphics with a little goof sometimes.
Go out and you have fallen in love with a game that is so much more.

10/10

PS: Currently. I have played through all secrets until the end of ACT 2 and played once through Layer 7 and don't know anything about future layers.