This game probably is not that unknown, considering it sold more than 1 million copies, but I still recommend it because it fantastically showcases the power of the human mind for anthropomorphism. The game is only made up out of rectangles. So graphicwise, a potato could run it.

The charm comes from the narrator and the characters (meaning the colorful rectangles you can control) he brings to life. The game is a platformer where each character has a special skill (can jump high or be a trampoline to others, etc) and you need to find the right combination of combining their abilities to reach the goal of each level.

The story isn't anything great, but with the narrator it feels much more emotional and at the end you don't see a small red rectangle, you see Thomas, who is not alone anymore, because he found some friends.