I started playing yesterday (albeit very late) and finished the first 3 campaign levels. I loved it. I didn't wanna wait to install the obligatory 8GB day 1 patch, and that meant I was initially a little disappointed by the substantial screen tearing in certain spots. I also thought they axed the FOV slider at the last minute as it was nowhere to be found in the menus. I was still having a blast. Not to worry, though: patch 1.02 takes care of both of these issues. This is a mighty fine looking game, with terrific lighting, wonderful creature animations, gorgeous Mars Vistas, kick-ass particle effects, great looking material shaders, Ratchet&Clank level motion blur and exceptionally clean image quality. And thanks to the framerate you're moving through the demon horde like a knife through butter. I'm also in love with the presentation in general. This game is angry like it's 1993. Doom Marine doesn't push buttons. He crushes them with clenched fists. Then he rips out an imp's jaw while listening to death/industrial metal takes on your favorite tracks from the original Doom OST. The baddie is impossibly sinister of course. Like Skeletor on a really bad day, with Mortal Kombat announcer-esque voice to boot. Doom (4) never pretends to be a grown-up like it's slightly po-faced predecessor. Instead it revels in the thick layers of cheese it's coated in. Do yourself a favor and suicide in the molten iron in mission three. Gave me a good chuckle. Gameplay is where it's all at of course. The thing controls like a dream. Folks are moaning it feels like Quake or UT. I'd have to agree that that is what it does feel like, except I think that's just about the biggest compliment you can give to just about any shooter. It's not Doom1 anymore and it shouldn't be. It has modern stuff in it like weapon mods, secondary weapons fire and something resembling parcours. It also has rpg progression elements like weapon and armor upgrades. These are good things as far as I'm concerned. The game feels old-school without ever being archaic. Heck, even the unobtrusive story seems sort of interesting so far.
No idea whether the game will be able to sustain its momentum of course, but since these games only tend to improve with the expansion of your personal arsenal, I'm not really worried here.