LambdaHack is a Haskell game engine library for ASCII roguelike games of arbitrary theme, size and complexity, with optional tactical squad combat. It's packaged together with a little example dungeon crawler in fantasy setting that can be tried out in the browser. (lambdahack.github.io --- It runs fastest on Chrome. Keyboard commands and savefiles are supported only on recent enough versions of browsers. Mouse should work everywhere.) A larger game built using the engine is Allure of the Stars.
Please see the changelog file for recent improvements and the issue tracker for short-term plans. Long term goals include multiplayer tactical squad combat, in-game content creation, auto-balancing and persistent content modification based on player behaviour. Contributions are welcome.