You may have some trouble fitting this large game in your window. But that's sure worth it. Protect different maps with nice towers.

Protect your gemstones from greedy creeps. Build and upgrade towers on different types of land to protect your collection of shiny gems.

A simple tower defence game with StarCraft sprites, nothing too special.

In this Christmas game you are trying to stop the carolers from reaching your house. And to do this you can use the six Christmas yard ornaments to stop them. No upgrades for your towers... Merry C...

Defend your girlfriend against lines of creeps, game from Addicting Games. Looks really good. Towers with a nice range too.

A 50 Kb tower defense game, buy different turrets and upgrade them with elements like Lightning, Fire or Ice, or give them power upgrades. All very basic and not that challenging.