I never really found the DKC games to look creepy. At the time I thought they looked incredibly cool and I figured that all future games would look like that (and I was right for a while; Square used pre-rendered backgrounds in FFVII). These days I can see the flaws so it doesn't look as nice. The sprites are quite pixelated and don't you dare play it on a computer monitor or HDTV.
At the time I felt the graphics made the game seem a little more serious. I like the look of a game like Super Mario World far better now but at the time (remember I was in my early teens then) I felt games like that looked a little juvenile. DKC carried a certain weight in its visuals, it had more emotional impact. I know that sounds dumb for a game about a gorilla trying to get back his bananas but that's how it affected me at the time. The music really connected with me. The underwater music was beautiful but somewhat sad while the factory music just felt like a panicky rush, perfectly matching the levels it was in. DKC is the first game I ever played where I felt the need to play the music to my parents, who don't care at all about any videogame. I even attempted to record a soundtrack by putting a tape recorder up against my TV speaker.
Nowadays I find the music triggers a bittersweet nostalgia, like I'm sad those days of videogame history are gone but I'm glad to have been there. DKC3 has a rendition of the castle music from Super Mario 64. Not only does it sound better than the source game (due to the SNES's superior sound chip) but I associate it as the end of an era. Here was one of the last major SNES games and it does a shout out to the next Nintendo generation. You could not play that game without being reminded that the days of games like this were over. It's rather suitable as a swansong for the SNES.
I notice those that found the graphics creepy are about five years younger than me, which would be a whole videogame generation. I could see how one could find those graphics creepy at a younger age. Stop 'n' Go Station is creepy but I felt it was supposed to be.