Basically, buy it because it's cheap might eventually lead to Mighty Rocket doing an Obscure 3.
Core gameplay is fun, the beat 'em up parts work pretty well, the characters are samey but have slight differences. Mostly, one "Always on" skill and some special moves, and the damage they deal with specific weapons. It's more fun with friends, but so is anything up to and including getting slaughtered by an ax-wielding maniac. Even the weapons are pretty samey, but it's fairly straightforward to start whacking enemies and never get touched, stringing S combos together in no time.
Not much in the way of story here, generic characters go to town on zombies because zombies are in the way of generic characters, eventually they run into token savior scientist. (Named Adam, no less! Only Heinrich beats that for cliche points!) Should mention that much like Corey from Obscure 2 was a Derrick Whitley expy from Sum 41, Sean is Jarle Bernhoft from Span, which is pretty cool. Although he's browner, for some reason.
Music holds up, although you might wanna pop the youtube repeat on. Horde music is always the same.
Overall, the first five levels hold pretty well, but here's the thing: It's an 8 level game with 4 effective levels, AND it's padded over that. Once per episode, your characters must stop beating people up to do something completely unrelated! Hey, let's toss boxes at this guy while we chase a train! Let's ride flyers and hit other flyers while we're at it! Let's play space invaders! Why? Cause... Those games were 2D too...? The minigames come out of left field and most of them do NOT fit well. When it's not minigames, it's lugging stuff around. Apparently Leafmore has a booming business in demolition. You can tell from all the nitro boxes laying around unsupervised.
As mentioned, you get new levels on 1, 2, 3 and 5, and the rest is repeated. You will surely be familiar with splashy world by the end of this game, tell you that much. It doesn't work against itself as much as you'd think: Being able to get a grasp on the levels quickly means you can blaze through them while racking up your combo the next time you're there, which you'll probably want to do.
You know when Obscure 1 pulled a bait at the end, and it was awesome? When you've just beaten the final boss, your character injects the vaccine, and then, in broad daylight, the final boss comes creeping back up to try and fight you until the very end? That underlined his human nature and the ♥♥♥♥♥♥ situation he was in, a man who had lost what very little he had left? Obscure 2 tried to do that, and... It brought back that one puzzle from 1. Hey, even then, my thoughts were "Hey, more game, cool." Final Exam tries to do that, with a cool minigame, followed by an okay boss, followed by another boss, followed by ANOTHER boss, followed by YET ANOTHER GOD DAMN BOSS ARE YOU KIDDING ME followed by EVEN ANOTHER BOSS ARE YOU EVEN oh it was a bait cool then.
So yeah, it keeps the Obscure formula, if a little mislead at times, it still makes for a fun game, and the best selling point would be that it's pretty cheap. Don't expect any of that caustic humor or videogame references they promise, though. Caustic humor never gets past "Fat guy dies ridiculously" and videogame references can be summed up as "Gordon Freeman had a crowbar, the cake is a lie."
Despite my tendency to underline the negative, I'd say grab it if it's in a sale. Or even if it's not and you like beat 'em ups. On it's own, it's a good game, and I'd say actually being tied to obscure, specially obscure 1, hurts it by comparison.