I've had both for a long time and I belive that the first one has the more dramatic music score of the two. I dunno why they changed the style to techno for the sequel, but it sounds good and fits nicely with the action.
It used to be all Kurt, now we got all three of them and finally the title name stands out. I'm guessing you didn't know this, but I remember some interview awhile back that Dave wanted to make the game play WITH all three characters, but between time and some differences between them, they just had no choice but to stick with Kurt and take it from there. Now if anything, I'd like to see a part 3 with the ability to chose whoever you like to play through the levels with on certain missions (remember the final level in MDK2?). I mean I would have laughed my ass off if I saw doc Hawkins going at it with the first boss from that miner level, purly insane!


btw, you can get a MDK/MDK2 combo for pc $9.99 now, so that's a great deal.