Based on the Impostors arc from DC comic's Detective Comics #867-870, which is partly based off the Jokerz gang from Batman Beyond and Sons of Batman from Dark Knight Returns. The set up is basic, batman's out of town so "The Bats", a bunch of Average Joes dressed up in their own ghetto versions of the cape and cowl, get a bunch of guns and attempt to protect the city. At the same time, a bunch of dudes who are joker-obsessed dress up like the clown and of course them and the Batmen come into conflic.If you were expecting a TF2 clone you are wrong in a few places, but right in a few others. 

Level of customization:

You start off with 5 presets a Sniper, a scout, heavy weapons guy, the average well rounded soldier and support guy aka MEDIC! You soon unlock custom classes and god damn dude do you have freedom, you can select 2 primary weapons(unlike COD or other FPS games which your secondary weapon is a different set of side arms and special weapons) with a modification slot for each weapon. You can choose body type (which dictate movement speed and life as well as how strong you melee is), gadgets to expand your characters movement and attack options like a ghetto hand-cranked grappling hook, Glider, Roller Skates, jump boots even smoke bombs. There's also support items(Armor, Throw-able objects from Boomerangs to IED, even some anti-gadget items), perks(playing dead, faster movement, resistance to x,y &z, better aiming) and tons of visual and audio tweaks (faces, voices that you can tweak in pitch) and that's before you get to costumes which can be customized for both Bats and Jokerz with various options that mostly goes together no matter the combination.

It just gets deeper as weapon and game play challenges(which can be viewed through the "track record" menu) unlock paintjobs for your weapons, as well as backgrounds and catchphrases for your "calling card", basically your in-game gamer tag. These calling cards have backgrounds ranging from patterns to Batman characters like Bane to Talia to Ivy and catchphrases of simple funny lines.All in all it'd be hard to come across someone who's got your same outfit, face, load out, and calling card

The Gameplay:

Without Gadgets it's rather standard FPS gameplay affair, with the available modes being propaganda and a variation of Domination/Base capture called Fumigation. For those unfamiliar with Domination/Base capture, there are 3 bases, each team spawn nears one and there's a third usually in the middle of the map or a position of equal distance from both main bases. The objective in Fumigation is to hold more bases then the enemy as a meter fills when the meter gets to 100% you win and the other team is slowly killed by the game one final time(which you get bonus exp for killing them during the slow killing section). As for Propaganda, it's basically there's 5 minutes on the clock, a battery in the middle of the map, you have to pick it up and plant it at the enemy base and hold the position for a good 30 seconds they enemy can disarm the battery at any time(but counter is still going), after that is done a shock wave stuns all enemies for 15 seconds and then you do it again when times up, you switch bases (basically now you're on the right and they're on the left) and another 5 minutes is set on the clock, whoever has the higher amount of successful battery plants wins.

Now gadgets change the whole game from a standard FPS literally, as grappling hooks can be used to not only grapple onto objects but people and has the possibility of killing them if the person has low health and then get over to the position. also you can get on to high positions other wise unreachable and snipe or just laying down cover fire. Spring boots is basically the same thing but you have a large jumping arc, so you can come down ontop of your enemies raining down fire. Rollerskates, through out the map there's ramps, just rolling around on skates  allows you to ramp and also increases your movement sped drastically however you roll alittle abit each time you wish to stop moving so you may not be able to get behind cover easily. Goggles, able to see through walls and tag people for your team to see, and you get extra points if your allies kill them so basically a support role that doesn't need you be healing or killling to get points. Smoke are cloaking devices so while they're becoming standard in Sci-fi shooters , this one's unique in that it's as long as you hold down the L2(or Left Bumper on 360) you stay cloaked but the cloak leaves a noticeable blur effect of where you are also you can't use your gun(you basically holster it so there's a pause when you uncloak before you can use it). And the crowning Jewel of this game, the Glider Rig, if you don't understand what makes it so good, you can jump at any point in this game and use it, and if you catch vents(which are decently spread out) you can clear the map pretty fast, and then you also have dive bomb attack which can also help you get around a good 3 times faster if aimed right.

And then there's rampage which customization mode was locked in beta but seems to be your Killstreak super mode. If this has even 1/4th of customization of everything else, it will be good shake up, especially if they have say a regenerative rampage that heals you even as you're taking damage, or a speed rampage. There maybe more as mutliple things were locked under "classified" and with 1000 (A thousand) levels of experience and unlocks(which I got to level 25 beta cap in 3 hours of playing) so there is alot more to this game.

The Style:

This game drips very TF2 style, but has it's own unique twist due to setting. The tutorial Mission simply called "Initiation" is very much in the style of a "meet the" from TF2 with kinda snappy dialogue and comedic tones. The banter in an actual match has many different fun versions of the same reactions to things happening (they're taking X base, were taking the base, enemy has more bases) so it will be a good 4 or 5 games before you notice hearing the same line from the announcers(each side has their own announcers). The player characters and the little written snippets for leveling up and unlocking stuff get repetitive alittle quicker but still are fun as people tweak the voices to be deeper or higher(which is funny to be killed by a big brusier who has a high female voice). The Art style is more abstract shapes and gritty, with most of the hud that look like stuff drawn on paper that a crudely cut out, the streets are covered in dirt, the menus are rustic metal backgrounds with doodles and scratches and dirt on them and some times you see a roach crawl by.

Overall:

This is a good shake up to the competitive market FPS, if you don't like those standard military shooters this may be more your bag, if you're COD fan who wants a shake up to the COD type gameplay you'll be welcome here if you're a batman fan who doesn't mind FPS games you might like this. The full game will have experience level cap of 1000, 100s items to to unlocks and other modes such as straight up Team Deathmatch, this game will have legs and that's before DLC. This beta pretty much sells me especially as this is a straight up downloadable game that will be 15 dollars and has me hyped.

My suggestion is really play it yourself if you got a PS3 it's gonna be open for the next week/week and a half and if you like it, it will be out before next month's end.