fheroes2 is a recreation of Heroes of Might and Magic II game engine
Haskell game engine library for roguelike dungeon crawlers
A game engine for console based text games
A cross-platform 2D game engine
Starter project to get a Phaser game environment up and running
Multi-platform game engine similar to old Megaman with a stage editor
Mahasona engine is an open source game engine.
Point-and-click 2D game engine
OSGET is the first open source mobile game engine template.