Monocle is a platform for writing 2D sprite-based games that is designed to have as simple as possible of an API while still enabling works of great sophistication. It draws inspiration from YoYoGames's Game Maker systems, as well as from the core engines behind the game projects I've worked on over the years (predominantly The Ur-Quan Masters and Sable).
The project is still in the design phase, but is rapidly advancing towards cursory implementation of enough features to back a simple game. Resource management, basic rendering, sound, basic forward kinematics, basic input processing, collisions, controllable Z-Order, and custom rendering logics are all present. The only major piece left is high-level game flow ("scenes", "object contexts", or "rooms"). That's still being played around with.