A singleplayer mappack – a whole episode, but almost every map is made by a different mapper (beginners and experienced) without knowing the other maps, with only given entrance and exit areas, so that all the maps could be joined in one big episode.
Good mappack that gets better as you progress especially the last map by Kane.
One map has annoying button hunt and having to use grenades on computer and doors without any hint at all.
Level design for most of them is pretty nice and gameplay is good too.