I've begun working on my game engine, currently named fastjam. Its intended use is quick and easy development of 2D games during gamejams.
The code can be found here: https://github.com/TZer0/fastjam
At the time of writing, it contains nothing but a simple TDD-setup and some testing-code. Currently, only compiling to JS works. Top priorities are to make it run natively on Linux and make the engine itself.
See the README.md for planned features.