the only difference is there's no resource gathering and no damage to your buildings. ^_^
http://www.downloador.com/flashgame/desktop-tower-defense/
Cool, simple fun ;D
(http://img480.imageshack.us/img480/1129/desktoptowerdefenseps9.png)
omG this games gets DIFFICULT!
(http://img165.imageshack.us/img165/425/desktoptowerdefense2jr8.png)
rofl looks like my second screenshot above was the right idea... Lotsa videos on Youtube (http://www.youtube.com/results?search_query=Desktop+Tower+Defense&search=Search) ("spoiler warning")
Also fun: try the "10,000 gold" fun setting -- you can see what happens when you upgrade each tower to level 5, etc.
I find the game really easy, even on the harder difficulty levels. Though I haven't been able to finish the "The 100" challenge yet (farthest I've got is about level 74).
Also - there's now a multi-player desktop tower defense. I've got invites @ www.casualcollective.com if you guys are interested.
http://www.casualcollective.com/register/4adec9a59dd6a83f
http://www.casualcollective.com/register/e8f9ce2c987a4b6a
http://www.casualcollective.com/register/7ae84a97162c9f6e
http://www.casualcollective.com/register/1bf2f3762016b1a6
The invite system allows me unlimited invites, but only 5 out at once - so if you guys use all those I'll post more up.
Casual Collective, a sneak peak (http://youtube.com/watch?v=s6eMKJDDbNs) (YT video)
"A first look at the community based multiplayer flash game site created by Paul and Dave, the people behind Flash Element, Circle, Vector and Desktop TD."