As it turns out it's more like Evolve, or possibly Warframe. At least in co-op mode - I didn't play Versus. You take a party of five into a level which is fairly similar to a MMO-style dungeon, but as a first person shooter. So the classes (of which there are many, although only half a dozen or so were unlocked) tend to be utility in one form or another rather than outright damage dealers. A healer, a sniper, a control, a ninja melee, etc.

The filler between boss fights was pretty dull, I felt. The bad guys were pretty much just robot bullet-sponges to stop us getting to the next interesting bit. On top of that there are lights and bangs and powerups everywhere, but those powerups are pretty small. So it feels very busy and confusing. The boss fights, though, work rather well. There were only two maps, but they both used stages and environmental interaction to incite some thought and tactics, rather than just blazing away at a big monster.
It feels quite like Borderlands, graphically and thematically, and we were laughing out loud at some of the dialogue. On one map the big villain was despairing at his chief robo-henchman deciding he was Arachnis Spider King rather than his given name of Geoff. On the other there's a multi-legged tank robot who you mutually escort, who naively blasts through the level with you, oblivious to your ship-board controller making it clear that it's on a suicide mission.

There's potential here, I reckon. Communicate what's going on in the game better, make the filler parts a bit more interesting, and don't fuck it with a stupid unlock system, and it could be a fine game. Probably not worth the £40 they're charging - definitely not worth that right now - but still worth a look next time it's free.