This expansion was really good, basically just a roguelike version of Octo Expansion. The color chips making every run different and sometimes making you really OP was great, but I wish there was more variation in the floors rather than color chips. I was also kind of disappointed when I heard there was no secret boss like Inner Agent 3 (Inner Agent 4 was right there, Nintendo).
If you're just looking to clear it once it'll be really short. You start with dualies, probably the best PvE weapon for Splatoon, though I can expect it'll take a pretty long time to clear it with every weapon if you want to open all the lockers (I have no idea how tf I'm gonna clear it with a charger).