OOH boy, this was, really hard and really easy at the same time. Finding the notes to match the vocals was what made my bad apple remix difficult, but this even more so. For the rest, the original was very open so I changed the bass layers completely, which I think turned out quite well. I haven't played Splatoon, but the sequel has taken up most of my time ever since I got it.
Noice. Use a different kick though. A punchier one preferably. Smooth down the bassline and maybe give the lead a vibrato in places as well as a slide on a few notes. Like the half-chiptune style a lot. Arps maybe?