Datafall - a "puzzle platformer" that runs in the command terminal (written in Python using Curses)
Schro - a cooperative maze game for two players. One player is the "walker" and directly alters the maze every time a piece of the maze falls outside their field of view. Another player is the "overseer" and can see a geometric representation of the maze and modify one piece of the maze at a time by clicking on its representation. The overseer also sees the random goal location and needs to try to guide the walker to that location simply by making changes to the ever-changing maze. And they can't change any piece of the maze in the walker's field of view.
Cataclysm: Dark Days Ahead - A fully playable open source post-apocalypse roguelike written in C++. I contributed a "collapsing rubble" mechanic when buildings collapsed (which could happen if they burned down or a vehicle crashed through them). The falling rubble caused damage to players/NPCs/vehicles when falling and left behind rubble piles that slowed traversal.