Cube Trains is a free puzzle game where you build elevated railways in a city. It features 3D puzzles, unlimited undo/redo, and smart placement of pieces. The non-linear level graph means you don’t have to beat a level before unlocking the next one. The game comes with a built-in level editor, so you can build and share your own corners of the city.
Linux users must compile Cube Trains from the source, at the moment. There is an old compiling guide which may still work, or at least provide a good starting point.
Buy the expansion pack and show support for Cube Trains! Get 11 more levels and a water tile for the editor. Absolutely no copy protection or DRM, now or ever.