Yo, Bro!
You can play Broforce alone, or with friends -- and although the co-op mode can be fun for a few minutes, the impossible-to-parse chaos quickly drains its entertainment value. Alone, though, the game's charming mechanics really have an opportunity to shine.
At its heart, Broforce is a run-and-gun action game, like Contra or Metal Slug, but faster: you can die in an instant, and a large number of things on the map are liable to explode at any moment (but you also respawn quickly, so it's usually no big deal). One of the things that makes it really unique is the destructible terrain, so as you shoot your way through the level, craters form and structures deteriorate.
You can use this destructibility as a strategic advantage, e.g. sneaking into a closed room by tunneling in from the back, or blowing up a load-bearing column to take out enemies above. Think, a two-dimensional Red Faction. Yeah, that's pretty awesome.
Another of Broforce's distinct characteristics is the "Bro" force itself: a cast of movie-inspired action heroes, each with unique abilities and weapons. One moment you'll be playing as a Blade knockoff, another as Ash from Evil Dead, and you might just switch from Commando-era Arnold to Terminator-era Arnold.
That "switch" is out of your control, and here's where it gets really fascinating. At first, you'll lament the fact that your character is randomly chosen, both at the beginning of the stage and when you respawn; and when you rescue hostages throughout the level, these, too will cause your character to randomly change. "Shit!" you'll utter, as your high-volume machine gun gets replaced with a short-range dynamite throw. It becomes impossible to approach a level with any intentional tactic.
But after a while, you'll realize that this isn't the point of Broforce. By forcing you to try different Bros with different abilities, the game is showing off its greatest strength: its varied and diverse sense of destruction. Getting too accustomed to one character or another would just make the gameplay tedious -- instead, you're forced to adapt to wildly different movement and attack strategies on the fly. Rapidly switching you to new characters, without your explicit control, ends up being a stroke of genius. (And even if you get switched to an awkward character and die, all you lose is a few seconds of progress.)
Although the core experience of Broforce already seems pretty solid, there are apparently a ton of features left in the game's development track. I'm looking forward to giving them a more thorough run-through once it reaches full release status.