Spent a bit of time and couldn't figure out wtf to do in 18/19 after getting the cube so I just edge glitched through the next 2 doors. If anyone figures it out lemme know please.
Also, the last level (after you finish the chambers) is freaking annoying as hell. That level alone basically ruined the entire thing for me. Up until then it was pretty satisfying playing it, but that made me never want to touch Portal: Prelude again.
More glorious Portal maps.
Linear Mode
