So Splatoon 2 is my most played Switch game since I'm addicted to the multiplayer modes. However, I've never been a big fan of the single player stuff in either the first game or this. Had to force myself through it in the first game and I only got about half way through Splatoon 2's before I just couldn't care enough to go further. Since Octo Expansion is focused on single player, I'm curious from those who have it how similar it is to the single player in the series from the past? Does anyone think it would be worth the $20 even for someone who hasn't liked Splatoon single player before? 

I haven't played the Octo Expansion yet, but I heard some of the challenges can be brutal. If you're looking for more of a challenge, then try the Octo Expansion. Personally, the single player in Splatoon is pretty good. The first game had a more basic single player while the second game had a more varied, but not too challenging single player. However, the first game's final boss was pretty epic and, while not as good, the second game's single player's final boss wasn't too shabby either.

I love the Splatoon single players, I love platforming, but if you didn't like it, you probably won't like the Octo Expansion either.

Nope. In fact, I heard it was even harder.
My daughter beat it in like a day, btw. I watched a little of the gameplay and it didn't seem very different.

I think you're fine just browsing deviantart to get the gist of it.

Something tells me Devian Art + Splatoon only leads to squiddie porn

Same as me, and yeah I dont we would like the expansion pack.
So I just watch a youtuber go through which seems to VERY HARD!

Well, yeah. But this time it's with even sexier Octolings!

I thought Splatoon 2's single player was extremely underwhelming, and while Splatoon 1's was neat, it wasn't exactly the most memorable thing.

Octo Expansion is a neat twist though, as levels challenge you to use different weapons in rather unique ways, and only a few levels are generic "start to finish" levels, so I would definitely recommend.

Splatoon's single player always get like a tech demo to me, so I've been wondering myself if the expansion is worth it for me...