Oh man, where do I start? I've spent the last ~4 1/2 hours playing this game (literally, the second it went live on Steam). These are my experiences:
One of the huge promises I was psyched about was "less is more". No headshots. No grenade spam. No lone wolf gameplay. This game was seemingly defined by what it *wouldn't* allow. Unfortunately, it seems that motif extended a bit too far and also includes "no content".
The game feels very bare. The single player campaign/story mode *IS* the multiplayer. There are a few challenges to complete, but ultimately you're left wondering, "What is there to do?". The weapon customization is pathetic. You have anywhere from 2-6 scope, barrel, magazine, and muzzle attachments and scopes are about the only thing that will actually make you feel like your weapon has changed (and that's only because it's cosmetic and you will see it in game).
Thankfully, however, class and character customization fare a bit better. Ultimately, no one category has a lot of options (more options than the guns, but that's not saying much), but there are so many categories to edit, that you'll ultimately end up with something that feels unique (though I wish the faces would've used an RPG-esque facial slider. All the pre-designed faces look pretty awful (just my personal opinion)). Class customization is equally as deep. You have a nice selection of abilities to choose from, though your initial choices will be limited 'til you level and rank up.
Speaking of which, nearly everything has to be unlocked. You initially only have access to 1 body type, 2-3 articles for each character customization category (minus permanent features like face, voice, tattoos, and scars which are fully unlocked from the beginning), 1 class ability for each class, ~5 general abilities, and about 1/2 the weapons (all weapon customization (silencers, magazine extensions, etc) is locked initially though). And it has to be unlocked everytime you make a new character. No matter what. Already unlocked all the Security gear on your Lv.20 Security character? Welp, now you get to unlock it all over again.
However, it's not a big deal because you can blast through all the game's content in a single evening. 8 maps and 4 challenges. That's it. "That's okay." you say. "Multiplayer is about replayability anyways." This is true, but due to Brink's structuring, and the melding of singleplayer and multiplayer, everything quickly has a "been there, done that" feel.
Everything feels very linear. Maps have a lot of choke points and, despite the parkour mechanics, there are not a lot of interesting ways to approach a situation (when your objective is up a set of stairs or down a hallway, you can't exactly tackle them any other way than "run up the stairs" and "go down the hall". So much for creativity).
On top of this, you never feel inclined to swap classes. Your class is defined by your class abilities. That's as far as your role extends. When it comes to shooting, all classes are the same. A medic can shoot just as well as a soldier. This ability to "hold your own" no matter what means you can't swap from a weaker support class to a stronger offensive class. I know this was done for the sake of balance, but what you're left with is gunplay that feels extremely homogenous.
Thankfully though, the class abilities are a wonderful, delightful shining star in an otherwise underwhelming shooter. All the classes are deep and have a load of abilities to customize once you've leveled up and unlocked them. All classes are also equally as important as one another in the grand scheme of completing missions.
Unfortunately, this is also my biggest gripe thus far. The game is *SO* team based, that it is absolutely impossible to do anything on your own. Which means if you're grouped with a bunch of idiots, good luck. "So I'll play offline." Ha. Ha. That's when you find out the bots are even worse. Also, at the time of writing, private matches seem unavailable or have errors on Steam. So there's no getting together a group of friends and going to town. You have to smash your head against a wall and play with the unwashed masses.
It's a shame really. This game has a lot of promise. If you're looking for a new team based shooter, I'd still recommend you give it a shot. It just needs more . . . everything. And if you are going to invest in it, make sure you have 4 or 5 friends to bring along. This is not a trip you want to take alone.