Overall I like it a lot, the best thing of this game is the soundtrack no doubt! I never thought Doom would mix well with a rythm-esque game. The songs are a banger!
That being said, I feel it's learning curve is a bit too hard like other comments pointed out. Even if the game doesn't always tell or show you what to do, it's somewhat intuitive and you end up learning fast how to play. I didn't notice your health meter is the character's portrait until 5 minutes into the game XD
I like the game over screens showing what killed you. It's a really nice touch!
Maybe the part I didn't like is how slippery the controls are. It feels like you can lose control of the character. It's hard to stay on the middle lane. Maybe a difficulty setting would be a good way to satisfy players that ask for it to be slower/faster? It's up to you!
I'd love to see more of this. New weapons and enemies, new areas to explore... I really liked the core mechanic of the game! With a good polish I'm sure it can be even better than it already is!