This is a general purpose 2D game engine, it provides many fundamental features that a typical 2D game needs.

It's built using JavaScript, and operates over HTML5 canvas. You will need to use JavaScript to build new games from it as well.

It provides game loop management, asset representation management, level management, input handling, collision detection, rendering, etc., check out "Features" tab for more detail.

Basically, if you want to make a new game from it, the engine has all the building blocks at your disposal to get started, and you'll mostly be worrying about design decisions and game logics, lower level jobs as mentioned above are handled by the engine behind the curtain, check out "Guide" tab to learn how to start making new games.

Also, I have some games made with the engine already, you can check them out at the "Samples" tab if you want to get some sense of what the engine can do, and how certain things are done.