Played through the two co-op missions with three different characters (Rath, Montana, & Oscar Mike) and I have pretty mixed feelings on it:
+ I like the humor and the characters have a lot of personality.
+ The boss mechanics are pretty good. They're pretty fun to fight and there are a lot of them.
+ A lot of people seem to hate it, but I like the art style.
- Combat feedback is pretty weak. This is a problem I have with Borderlands and it transfers over here.
- The co-op missions are too long (The Ice level in particular). I wasn't timing my playthroughs but whatever length they are is a lot to ask of a matchmade online co-op game. They need to be split up in half or maybe even thirds.
- There's too much going on on-screen if you're a melee character. I really didn't have much of a problem with the ranged ones but once you start slashing with Rath it's very hard to see what you're actually doing or hitting (which is exacerbated by the feedback).
- The FOV is way too tight and the characters take up too much of the screen. This makes the previous point worse than it needs to be.
- Mobility is too limited and the characters feel too slow for a lot of what they're trying to do in the campaign. For example, there's an enemy that can dash from really long distances directly in to your face and tear you up and there's really fuck all you can do about it. There are also snipers that give you warning with laser sights, but there's not much you can do to dodge them besides slowly and clumsily serpentining if you're not next to cover (luckily they're terrible shots). Rath has a double jump upgrade but jumping with him feels terrible and doesn't even go that high. Maybe it's just the characters I've used so far, but I feel like this game could do with a mobility overhaul across the board.
So overall, I don't know. I feel like the campaign would be a pretty fun run through for the bosses but not so much in between. The characters I've tried are on the verge of being fun but have a lot holding them back. The funny thing is I think a few of the bigger playability negatives (particular FOV and screen crowding) would be basically eliminated if the game was 3rd person and I bet it would be a better game if it was. I'll probably still give PvP a shot, but I don't see it winning me over enough to get me to pick this one up.