First of all, the track you've decided to remix is in my opinion a very hard one to remix. That being said, unfortunately I think this mix has many, many problems that doesn't make it sound very good. I'll list some of them here:
-The very beginning sounds good enough, but the...whatever it is that comes in at 0:06 sounds is just wrong. It just sounds fake, and I don't even know what it's supposed to be. You could try some nice strings here, perhaps.
-At 0:26 there's a weird note that just pops up from nowhere. The instrument is not heard afterwards (I think?) so it seems a bit random.
-Drums lack punch
-I see you've tried to recreate the "ghastly sound" at 0:40, but it doesn't work. It sounds like my grandmother moaning. Even the original sounds better, though I don't really see why the moaning should be there at all. It just sounds kinda silly.
-The sound that comes in at 0:54; that I like! It sounds C64ish to me. That's a plus.
-Though at the same time I'm hearing that the bass could be a bit crunchier.
-1:07 break sounds good, though it would work even better if it really started to build up speed here (not talking about tempo)
-The solo sample used in 1:35 and onwards could be a bit better. Also there was no "kaboom solo segment in your face" moment here that I was hoping for (related to previous comment)
-The thing that starts at 2:01 sounds really awkward and out of place. Do not want.
-The sample used in 2:14 is OK. The solo starts off smoothly, but the rest of the solo could be better. It seems...careful somehow, when it should go all over the place. It is a roller coaster after all. Now it's mostly in the mid range.
-The part at 2:42 is likeable in a weird way, however when it comes to that regular beat after that, I'm feeling you're running out of ideas at this point.
-The ending is kind of a lackluster and seems really simple. No fireworks there neither...
So, as you can see there's a whole lot of stuff that need to be addressed in the mix. Also, I might point out that this mix is quite close to the original. There were solos and stuff yes, but still. The mix also lacks general punch and in-your-face attitude I think it should have. Now, the mix seems very tame. This roller coaster ride was really slow, quite boring, and very straightforward. Sorry.
Now, how to fix these issues? I'm no untz expert so it's hard to say sample-wise, but what I think is most important, is to add more of your own elements and more originality to the mix. The year is 2008, and the original was made in the mid-90's(?) so you don't have to follow the original that closely. Imagine you're on the roller coaster when you're listening to your song; make it seem wild. Maybe you'll come up with an idea on how to accomplish that. Also, try to find better samples. Most of them sounded bad.
</my two centipedes>
edit: also, I might add in conclusion, that I totally respect your attempt on this mix. The original is one of my favorite tracks in DKC2.
edit2: one more edit: the song had no file extension for some reason or another when I loaded it from mediafire, so people out there if you want to listen to the song add .mp3 to the file name.