Data-driven
Every aspect of the game is controlled through text configuration files. Before shipping, configuration files are compiled to efficient platform-specific binary blobs.
Data-oriented
Data in memory is organized to achieve the maximum performance possible on every platform.
Fast-iteration times
Every game asset is hot-reloadable, code included. Evaluate modifications and adjustments on-the-fly without having to reboot the game every time.
Cross-platform Editor
Runs and looks equally well both on Linux and on Windows. Designed to be as fail-safe as possible to never lose your work if crashes should occur.
Lightweight codebase
Engine plus tools amounts to less than 50K LOC. Written in simple 'C-style' C++. It is easy for anyone to understand and make modifications.
Free and Open Source
All the code is released under the very permissive MIT license and can be downloaded via GitHub by anyone.