I too love Tower Defense a lot, they are the best flash games on the net, I'm currently playing Onslaught at the moment.
Here's a great site for some Tower Defense games: http://www.towerdefence.net/?page=allgames
Nintendo still doomed?
Feel free to add me on 3DS or Switch! (PM me if you do ^-^)
Nintendo ID: Mako91 3DS code: 4167-4543-6089