There are a lot of different Bowser Castle themes in the Mario Kart franchise, but the version from Mario Kart: Super Circuit has always been my favorite.
To be honest, I was looking for an easier song to tackle since I'm still reeling a bit from Sonic Fan Medley 2 and Star Dream xD. I realized we could use more variety in our Mario Kart songs, (that aren't Rainbow Road, haha) and remembered that I've always wanted to do this song.
There's a lot of great MK Bowser Castle themes, but this one's always been my favorite. It's just so... Bowser. The guitar riff in the first part of the song is actually very similar to the main rhythm riff in Bowser Battle 64. The rest of the song is very classic thrash metal sounding, and the part where the synth strings takes over always reminded me a little of Symphony X material.
I kept this remix pretty simple and straight forward, running through the song a couple of times with a solo section in the middle (brought back the wah like I did in Bowser 64), and experimented with a metalcore-ish breakdown at the end.
I still plan on knocking out 1 or 2 more Mario Kart songs this year, so stay tuned!