Some of the gameplay of GlPortal is similar to Portal, but the game is not a clone.
I think Portal’s graphics are still up to date enough to be the best possible Portal at the moment so I see no need to violate Valve’s copyright and create a copy (that no doubt would be inferior to the original). However, since GlPortal is open source, you can push it in every direction that you like. Just fork the repository on github and change the code however you like.
GlPortal is even better
While GlPortal is a free puzzle game that is in some aspects similar to Valve’s Portal games. It does by no means try to copy these titles. GlPortal will feature a unique story and a lot of elements never heard of in other teleportation games like Prey or Portal. So basically, it is much more than a free portal clone. Get your copy at the download site.
What GlPortal can be
Help shape the future of GlPortal. We are looking for community managers, developers, artists and testers. Just register and write a message in the corresponding group. If you want to help and you are not sure what you can do, just stick arround in the groups and you might just find a task that fits.