Welcome to Principia
Principia is a physics-based sandbox game. Build and play advanced contraptions, circuiting, minigames, puzzles, robot adventures and more. Open source, free and available for Windows, Linux, Android and more, download it today.
This site is the new community site for Principia. When you have installed Principia, enjoy the levels others have created, and register in order to upload your own levels and interact with the community.
Want to read more about Principia?
Also check out...
And the Official community site archive, an archive of old levels spanning from 2013 to 2018.
Apparatus player? Check out Principia for Apparatus Players on the Principia Wiki!
Featured levels
Latest news More
- 2 Mar 2026New contest: Daft Dummy!
- 16 Feb 2026New contest: Crazy Circuitry
- 31 Dec 2025Principia in the web browser, and more...
- 6 Jul 2025Follow Principia on YouTube
- 14 Apr 2025New contest: Puzzling Puzzles
Top rated levels More
Latest custom levels More
Latest adventures More
Latest puzzles More
Glados commented on Simple battery level indicator: 4 hours ago
@randomguy123 how? Try itrandomguy123 commented on Stupid dummy becomes ground beef and gets delivered: 5 hours ago
Galaxium, what's sus about it ???randomguy123 commented on Mr. Cuddles (Prototype): 5 hours ago
Can it eat dummies ?randomguy123 commented on Simple battery level indicator: 5 hours ago
You could use it to build a machine btw, it's smart 🤔ROllerozxa commented on Stupid dummy becomes ground beef and gets delivered: 1 day ago
(GONE WILD)Galaxium commented on Stupid dummy becomes ground beef and gets delivered: 1 day ago
Why does this title sound so sus 💀💀💀Glados commented on Help with camera: 8 days ago
@randomguy123 It's supposed to follow the line position, but the camera is broken and doesn't work properly@owhame answered here
ROllerozxa commented on Thing: 8 days ago
Whatever it is, it sure can fly...