I am a huge fan of the old EGA Commander Keen games released in 1990 and 1991. I have been playing them since 1995. There is a rather large fan community for Commander Keen. When we heard there was to finally be a new game, we were elated. We had been pestering id for years. I suppose you can say that this game is our fault.
They quickly got together a no-name developer, a big-name publisher, and id (the owner of intellectual copyrights). They produced a bad Mario clone with a character whose helmet is the wrong color, the enemies are killed the wrong way, his gun has the wrong shape, color, and name, his clothes are the wrong colors, and many other things which exclude it from the other Commander Keen games.
Unless this is the first game you have ever played and are captivated by a character who jumps when you press a button (or not, depending on the mood of the console), you might enjoy this game. Otherwise, don't buy it. If ...