It's so disappointing in so many ways - it's like the devs tried copying Doom without knowing what made Doom so fun to play.
Weapons are underpowered, ammo is scarce, and the sound design is the polar opposite of 'punchy'.
Levels are symmetrical, and filled with way too many monsters for the flimsy weapons you have. Textures are reused far too often, resulting in additional confusion while navigating. Many lack any kind of climax.
Enemies are confusing (ghost variants, projectile variants), and have way too much health.
The worst thing is that it could've worked really well - there's bits and pieces of a really cool game in there (I LOVE when you get a new weapon and Corvus does his evil little laugh). Does anyone else feel this way? Or am I just a complete grouch that needs to learn to have some fun...