Is there a multiplayer coop?

[Schrödinger's Cat]

Want to find a TD game to play with a friend; this one looks really good

[BilboCGL]

No.

[Sonicthebitch]

Sanctum 1 and 2
Orcs Must die 2

[Schrödinger's Cat]

Thank you guys

[Origan]

pixel junk monster ultimate a good one :)

[Lars]

Defense Grid 2 also has online modes. There are of course also the Dungeon Defenders games.

[Le Deflagosseur]

Sol Survivor