Tuxmino is a free open source falling block puzzle game. It is highly customizable and has LUA support so users can create their own gamemodes. Tuxmino is written in C and uses the Raylib game library.
Lua Game Modes
The main feature of Tuxmino is that it has support for making your own game modes. It has integration with lua, so users can easily create and share their game modes without having to recompile the game. This means users don't have to worry about maintaining a copy of the source code, or worry about how to use a compiler. They simply just need to add the lua game modes in the gamemodes/ folder, and the game modes will appear in-game. Lua is also a high level, easy to learn scripting language, so anyone can make a game without having to learn C.