The listing, Only One Rectangle (Steam Key) has ended.
https://store.steampowered.com/app/1275410/Only_One_Rectangle/
About This Game
Only One Rectangle - platformer with a variety of disorienting gameplay for an interesting gaming experience. A lot of colors, invisible painted platforms, traps, various puzzles.
- 50 levels with different difficults
- One hero, one goal, one exit
- Rampage of colors