Here some usefull user comments;
Probably the hardest thing I've ever seen in portal, and I've played quite a few custom maps and know quite a few tricks... the sickest thing about this tormenting game is that it actually has advanced 18th and 19th chambers! As if they weren't damn-near impossible already! I'll tell you what- anyone who can get through 19's long chute without at least 5 quicksaves/quickloads is a god. I scarcely believe it's humanly possible...
Great plot, but highly challenging. If you're not a pro you might want to bind a key to noclip to get around some of the hard parts, just to get to the excellent ending.
Overall this was an excellent mod, save for the terrible english voice acting, a few spots of clipping, and the almost ridiculously hard levels. If you're looking for some serious portal challenges though, it really doesn't get any better than this.