MicroTD

MicroTD (uTD) is a completely public domain, free software, suckless retro tower defense game. It was created by drummyfish as a C rewrite of a game originally made in C++ for Arduboy. The game is available under CC0 waiver and runs on the creator's simple game engine called SAF which makes MicroTD extremely portable (it can be run natively on PCs as well as in web browser and on variety of embedded open gaming consoles). It runs in 64x64 resolution with 256 colors and has simple sound effects.

8 towers and 11 enemy types are available in MicroTD, as well as 6 maps to play. Every tower can be upgraded and every enemy has unique attributes, for example ice towers that slow enemies down are only half effective against wolfs, ghosts can not be physically harmed and big spiders spawn two small ones when they die. The goal in each map is to reach as high round number as possible.