Nihilanth's death stopped any future alien attack on Earth. But after some time, there raised something more evil. It was called Mother of Headcrabs. This monster started creating more powerful headcrabs, than anyone could imagine. There was a lot of varieties and different specialities. They were true warriors, really strong enemies... - By Michal Jirouš.
Games and mods exist for one reason, to be fun; and to be fun it needs a challenge. This one DOES have a challenge, but it pushes it to the limit... It's so hard, the only thing I had a harder time at was trying to have fun. However I did like some of the things this mod added, one of them were the different types of headcrabs; even though they were very simplistic. Red= Instant kill, Blue= Freezes vision, Green= Toxic, and the Pink one doesn't even do damage; but still worth mentioning. Only thing I had a REAL problem with though were those Tesla-powered vortigaunts or whatever they were. They charge up more than twice as fast and when they do, they discharge the amount of electricity Las-Vegas uses in a year. Even though it wasn't that fun, there were some pretty neat things that I think deserve some credit.
5/10 is a fair rating, no matter how many people rate it 1/10; I think you should check it out.