So here's how I came up with my entry:
I knew I wanted to to do something with Mortal Kombat and I wanted to try to do something easterny sounding (kung fu-ish) maybe with some interspersed "eee-ya" fighting sounds or the like.
I came up with a easterny sounding riff which went like so:
I liked it and then decided to toughen it up a bit so I added a driving rhythm guitar which sounded like so:
But then when I tried to play my easterny sounding melody over the baseline, it just ended up sounding blues-rocky and very pentatonic:
I spent some time trying different things to keep the easterny feel, but failed miserably, so I switched gears to some more metal-y sounds.
The only metal song I've learnt recently is South of Heaven by Slayer, I slapped most of the main riffs into this little track:
Playing with the intro riff, I came up with the main riff of the metal combat entry:
And then the main rhythm riff was changed a bit as well. This track has the Slayer riff first, and my modification second:
So then it was just a question of turning the various bits into a song. I was hoping for the BPM to be a bit faster, around 150bpm or so, but I realised I can't reliably tremelo-pick 16ths above 120bpm, so 120bpm it was. Youtube for "120bpm metal drum track" yielded the drum track (the fourth or fifth hit has a good double-kick that I liked), and then Youtube for "Mortal Kombat Sounds" yielded the samples to lay on top.
I wanted to put in a part with two guitars in harmony --- the timing is bad and it doesn't sound great, but I left it in just because I must've blown 30+ takes on it and I didn't want to bin it.
I played the bass using an electric guitar with an octaver. The bass is super-boring, I would like some tips from the djentmeisters amongst you.
So that's the story! I hope it's useful for at least some of you, I quite enjoyed mapping out my thought process.