Splitformer is platform game that bases on premise of splitting game window and using it to move between them

Menu is navigated using mouse and ESC key (complementary to back button)

Levels are navigated with WASD keys and mouse (left-click splits window vertically, right horizontally)
Your goal is reaching green rectangle with player character. Everything apart from goal and dark rock can be split.
When you want to merge windows click 'm' key

In edit mode (when editing or creating new level), you can place tiles by clicking or dragging your mouse.
Tiles type can be changed with mouse scroll (small rectangle in upper-left corner shows currently used tile).
If you want to save level click s, type your new map name, and save with enter (if you want to cancel click ESC).
To test your level you can use T to change mode to normal gameplay, and to turn back to editing.

And that's all, so have fun.