Absolutely awesome game! I loved the original, and I love this one 10 times as much. More graphics, more sounds, more enemies, more weapons, more options, more... everything! The best that CDogs could've ever been, is this.
The only aspect I'd rather be different is the fact that enemies suddenly disappear when killed, whereas in the original they would turn to ashes (i.e. a generic, simple death sprite). Having said that, the blood effects are top notch, as well as the other effects (smoke, explosions...).
There are details such as the bullet cases, smoking guns, explosion debris, the walking sprites, character customization, and revamped HUD that add a new layer of eye candy which is much welcome, while steel retaining the feel of the original game. And the homage to Doom blew me away!
All in all, hats off to a great homage to an all-time classic!