Well there's a homebrew game called Warcraft Tower Defence you could check out. The only thing is you gotta download your own maps which isnt that hard... put em in a folder called "maps" on the root of your card.
unfortunately my g6 lite does not support homebrew
but in case you like tower defense games too. try out this free pc game:
http://www.kongregate.com/games/gameinabottle/gemcraft
QUOTE(Donato_Dobango @ Jan 27 2009, 02:54 AM) Eco-Creatures Save the Forrest has a lot Ninjatown's cartoon charm and similar gameplay in an RTS/defense style. I think anyone who wants more Ninjatown would enjoy it.
Locke's Quest is a bit like it, too. Robopacylse would be good, too, if you are looking for more of a strategic game with a similar humor.