When Keen:Modding first started up, there was talk of a Commander Keen Community Mod--something that the entire Keen fanbase could contribute to, an epic mod featuring work from everyone who wanted a piece of the pie. While this mod isn't quite so eclectic, it represents a powerful showing for just how good a Keen mod can be with more than one author.
The levels range from gimmicky to intense, scattered about with no real learning curve in sight--but this mod isn't really intended to be a stand-alone package. It's a mod in all terms of the word--a player is expected to know his/her way around a Keen game even before the mod begins.
Overall, this mod performs solidly, with nothing in particular helping it to stand out. If the CKCM ever becomes a reality, expect something of this level. Until then, this is more than good enough.