CSSBattle is described as 'online CSS Code Golfing battleground. Here, players from all around the world try to visually replicate "Targets" in smallest possible CSS code and battle it out to get to the top of the leaderboard' and is an website in the Development category. There are more than 10 alternatives to CSSBattle, not only websites but also apps for a variety of platforms, including Windows, Linux, Mac and Steam. The best alternative is CheckIO, which is both free and Open Source. Other great sites and apps similar to CSSBattle are CodeCombat (Freemium), Screeps (Paid), Robocode (Free, Open Source) and Bug Brain (Free).
CodeCombat is an online game that teaches programming to learners as young as 6. Students write code in real programming languages. No experience required! - How much does it cost? There are 110+ FREE levels which cover every concept.
Screeps is a massive multiplayer online real-time strategy game. Each player can create his or her own colony in a single persistent world shared by all the players. Such a colony can mine resources, build units, conquer territory.
Robocode is a programming game where the goal is to code a robot battle tank to compete against other robots in a battle arena. So the name Robocode is a short for "Robot code". The player is the programmer of the robot, who will have no direct influence on the game.
Colobot Gold is modified version of the original Colobot game released by Epsitec under open source (GPLv3) license. Source code was refreshed and rewritten using SDL and OpenGL libraries, thus making it multiplatform
VIM Adventures is an online game based on VIM's keyboard shortcuts (commands, motions and operators). It's the "Zelda meets text editing" game. It's a puzzle game for practicing and memorizing VIM commands (good old VI is also covered, of course).
You’re a machine learning specialist who makes neural networks but your cat seems to be better at it. Now you must solve puzzles to build a cat-to-human translation system (who knows what else this cat is capable of!).