Strategy game for someone who likes tower defense

[Kestrel]

This is for a person who likes Defense Grid a lot and enjoys plants vs zombies.

Looking for something else, but he does not get excited about flash tower defense for some reason.

Something easy to pick up and play (no complex controls)

Anything come to mind?

Thanks!

[Tals]

There is 3d Tower Defense on Steam at the moment - on sale for the next few hours at £1.50. I picked it up and it's quite enjoyable

http://store.steampowered.com/app/18500/

[dbt1949]

I have hundreds of hours invested in that game. Greatest investment I ever made.

[dbt1949]

There's also Plants vs Zombies. A favorite of a lot of people.

[Tscott]

If you find something, please let me know.  I'm the exact same way.  I LOVE Defense Grid, I LOVE Plants vs. Zombies and have been looking for something similar too.

I think PixelJunk Monsters might have been the closest I've come, but that's a PSN exclusive.  You could also check http://www.towerdefence.net/ and see if something there works, but I don't recall finding a clear winner when I checked that site out.

[warning]

I've never played it, but I understand Immortal Defense is available as a "pay what you want" sale now.

[Kestrel]

Thanks, everyone.

I guess he'll stick with Defense Grid: the Awakening and Plants vs. Zombies for now. 

I hope that Hidden Path works up another version of DG.

Merry Christmas and Happy New Year!

[Zero]

Someone on here (on another sub-forum) said that Gratuitous Space Battles (on sale at Steam: http://store.steampowered.com/app/41800/) is tower defense type game.  I'm thinking of getting it, and for $10, it's not very expensive.

[Elmo]

A lot of reviewers have given AI War high marks.  It's an innovative look at tower defense.  Just picked it up yesterday on Steam for $10 so I haven't formed any opinion yet myself.

http://www.arcengames.com/