After probably over 10 gigs of patches later, it's simply an alright game.
Being able to kill dinosaurs will cool guns is certainly entertaining, and if it had launched in its current state, the game probably would have received closer to a 70-80% on Metacritic, but that's not saying much because Metacritic reviewers are infinitely too easy on their games in my opinion.
Unfortunately, even with all the patching and updates, and I absolutely applaud the developers for sticking with the atrocity long after everybody gave up on it, it still has some major problems. The pacing is extremely slow. Prepare to use a pistol and a small weapon for a long time, even on the easiest difficulty, because you gain money so slowly you have to wait so many rounds to get the really cool stuff that it's insane. The rounds get really repetitive. There isn't much variation between the dinosaurs, they all basically do the same thing which is 'attack'. Sure some of them have different abilities but in the end it doesn't seem to matter much. Fighting some of the really big dinosaurs (like T-Rex and Triceratops) can be really cool, but you see them so rarely, and it's so easy to basically glitch them to death, that it takes most of the enjoyment out of it for me. My typical tactic for playing the game is playing the Assault class, buying a light rifle after a couple rounds, then flying with my jetpack up to a spot on a cliff and killing dinosaurs by the hundreds with impunity. There are really very few mechanics in the game preventing you from "cheesing" it like this.
They've recently added some really cool weapons, but once again, you gain money so slowly that even though I started playing again just to try them, I gave up. I shouldn't have to play 3-4 hours just to test out a new weapon for heaven's sake.
Basically, if you like this kind of game (wave-based survival against a much stronger and more numerous opponent), buy Killing Floor. You'll have infinitely more fun.