Game Platforms & Versions 

Trinagon comes as a free trial game with enough content to keep you going for likely .. months.
The Full Feature Unlock is possible in all downloadable versions.

The Full Featured Version (paid) in Virtual Reality 

Available free on the major app stores with In-App Unlocking :

Play Online & Free Download (unlockable) for PC, Mac & Linux 

The Itch.io page  contains the  download links for the unlockable versions and the online WebGL Game.
The latter is the same as the unlocked versions. It doesn't have a functional Unlocking mechanism, but is good enough to get a good feel for the game.

Enjoy puzzling !