Co-op

[FantasyFreak_UK]

Any good?

[Darkness]

It has online coop for 2 players.

Some people have some trouble joining each other, depending on various factors, but the devs are constantly making it smoother.

If you want to check some coop gameplay:
https://www.youtube.com/watch?v=OJtlrJuMhCs&t=14s

[Lars]

Bought it for co-op but haven't been able to join lobby with my friend yet.

[BlackjackGT]

imho it's a blast if you play with someone who "works with you' as opposed to someone who's rushing across the map. There's no screen lock as in Helldivers or The Nine Parchments. That's fine but if you work too far apart, you won't help each other at all. While it has friendly fire, I've rarely noticed any issues with that although you have to watch it with items like Ripsaw Blade that can wipe out both of you if shot in the wrong place. :)

Good opportunities for cross-fire and teaming up on the toughest "bullet sponge" enemies.

Here's my couple recent editied co-op videos.

From Late Beta:

(few levels past 1st boss level)
http://steamcommunity.com/sharedfiles/filedetails/?id=1327322147

From release version on Saturday (March 17)

(levels 1-4, Central Server Boss room, Levels 5-6, and briefly on 7 before my PC froze)
http://steamcommunity.com/sharedfiles/filedetails/?id=1335283949
I think it's still a bit confusing to know what chests can be used by both players, and which ones only supply one player.

Since there's currently no way to revive a fallen player, if you get whacked early in a level you might have to essentially sit and do nothing for 10-15 minutes until the other player reaches the exit teleport pad. Devs seem to be considering some form of reviving in co-op, perhaps at some fairly steep cost of some kind.

They still have crash issues, MP stability issues and perhaps router port issues to continue working on. I can't really say why Game Maker's online play requires so much router port gymnastics that I don't recall encountering in other games/game engines.