But addictive, but jelly defense is a lot of fun if your device can handle it. Minimum specs are a dual core, my nook tablet plays it great, and my LG spectrum handles it, but my Samsung moment and HTC Evo 4g cannot play it.
I spend a good bit of time on armored defense and a td variant cartoon wars. Arel wars is fun as well.
Other td games I've enjoyed, that are still installed in my nook:
Defender II
Empire defense
Field runners
Gave defense
Guns n glory
Hex defense
Ld dungeon
Ld shrine
Living dead defense
Sentinel 3
Swamp defense
Tower raiders 2
Z defense