tower defense games e.g. orcs must die

[unwashed potato!]

looking for some suggestions. can be on xbox or pc, though prefer pc if possible.

looking for tower defense style games. have played a few over the years, most recent being orcs must die and dungeon defenders.

the other player is a girl so i imagine sci fi ones will less likely appeal to her but will still be interested to hear all suggestions

 

[unwashed potato!]

i should also add we'd like coop rather than against. and also i think the reason we liked orcs must die so much is because you're a single character yet also have the turrets, so you get the best of both worlds. the fighting as a single person against an army, but also the towers to upgrade and plan