Open Surge is a free open source 2D retro platformer type of game for Linux, Windows, MacOS and android. This game is heavily inspired by Sonic games. This game also comes with game engine. Using this you can create new levels for your games. Not only levels, items, bosses, gameplay mechanics, playable characters, special abilities with its build in level editor and game engine. It is written in c and Allegro library and released in GPL-3.0+ license. This is really a fun game for all age group.