Honestly, whatever your favorite level is will probably be a good speedrun. My personal favorites are Level 3, 5 and 21. Just stay away from octavio

Most of the tutorials & information is on the Splatoon speedrunning discord server, https://discord.gg/GuSyHF8NT5

HM is short for Hero Mode, the free single player. For NG+ Octavioless, video evidence is preferred. But for runs better than 52 minutes, permanent video proof is required.

I thought sub 18 was possible. GGs