Brink was rented.
Edit: You are a resident of the Ark, a floating city that was used as a back-up plan for if the world would flood again. Turns out, it did. It has been an incredibly long time and the game takes place 20 years after the last boat or plane sighting. You pick to either be on the guys who wants to save the Ark, or one that wants to escape it. Now, both sides are balanced in morality: The ones who want to save the Ark seem good in intentions and so far it seems that they only want to establish order to maintain peace. The ones who want to escape are doing so in attempts to find land that is no longer flooded in hopes of finding a saving grace for humanity. Both sides go about this in the same way: Kill the other guys so you can complete your goals, instead of doing something like establishing order by giving the rebels a few boats and a plane to scout for land while the rest attempt to do something productive like make crops.
The rebels live in the slums, and tend to have rickity looking armor and weapons. The guardians have the modernized appeal, with sleek weapons and apparel. I chose the rebel side first, then tried out the guardian side. There is no difference in the least, save customization and level counting. (you cannot level up a guardian when playing as a rebel, for example)
So first off, you get a nice starting selection of weapons, 'avatar' customization options, and being able to pick abilities that will enhance your character, either through each single class or from universal abilities. However, you unlock guns, attachments, and apparel/accessories by completing challenges. These challenges are indeed challenging, which is good. What is not good would be the fact that the bots you fight with and against will often engage in firefights that involve standing in the open and shooting at the other guys. This goes against the 'Move more than you shoot' stratagem that the introductory video HAMMERS INTO YOUR BRAIN via constant repetition. Oh, and the introductory video that gets you to lv 2/3 right away is more than 20 minutes long.
I expected it to play like TF2 and Mirror's Edge because that is how it looked to be set up, class wise and combat wise.
Fortunately, it works just the same as those two games. Unfortunately, it has the worse of both worlds. The worse from TF2 is that the campaign is not even a campaign, but a roughly narrated series of scripted skirmishes played out against the AI. AKA: It was meant for multiplayer, and anyone who thought that it was a good idea to get it when they do not have an online account is sorely mistaken.
The less than appreciated part from Mirrors Edge would be contact detection, and the lack thereof. Free running around the maps is enjoyable, yes. Free running while being shot at or while trying to chase an AI is a pain at best. As much as the AI will stand out in the open it will also perform the most effective free run course to the objective and get to it before you can do the same even when you're a Light weight body type and they're a friggin heavy. Seriously. Heavy = slower than Medium, Medium = slower than Light. You cannot even keep sprinting when you're a Heavy type, it's short controlled bursts that take a good five to six seconds before you can use it again. Speaking of running free running courses, while you try to chase a few runaway cowards from combat they will try out evade you in the most effective means possible, while you try to keep up via copying their movements... because otherwise they outrun you or set up a one man ambush around the corner: aka slide and take out your legs, then melee you before you have the chance to shoot. THIS IS ON NORMAL DIFFICULTY BTW.
I honestly regret having rented Brink even if it was only $4. It still is a good game in multiplayer, because then you are not dealing with bots that are set up to difficulty sets that are higher than advertized, and do not instantly recognize a disguised Operative. COD: Black Ops did not get me this frustrated with a game, and only got me to yell out in anger when fighting against an entire team that only used Ghost, Warlord, and Second Chance. Mirror's Edge got me to yell for the exact same reasons: Trying to jump to a ledge and not detecting it, ergo falling down into a firefight that you are outnumbered with, or having to try to restart your run because if you go another way you get shot down right away.