"Fan-Made Portal Revolution: Free Prequel Mod with 40+ New Chambers"

After eight years of development, the highly-anticipated Portal: Revolution mod has been released, offering a brand new story set between Portal 1 and 2, with eight hours of gameplay, 40 new challenges and test chambers, and new mechanics. The mod has received a 'Very Positive' review score of 94% on Steam and is being praised as feeling like a fully-fledged expansion, with some users even stating that it feels like a legitimate Portal game. Best of all, Portal: Revolution is completely free, although players will need Portal 2 to play it.