I can see why some don't like this as much as the first one, but there's many reasons as to why it's better or at least as good.
The controls are so much more responsive, the game is faster, has better music and graphics and plays pretty much the same.
Only difference is, is that there's now 3 people to play as. A 4 Armed Dog, Kurt and the Prof.
But basically the game is the same mix of action, platforming and puzzling that MDK was and it's got 10 massive levels with a boss at the end of everyone. And the final level has to be replayed another twice to get all of the endings (Beat it with everyone).
So if you liked the first, try this one out, it's worth the cash and I think you'll be surprised.