"hey captain, I've got the Acorn"
"k, I'll give you a thousand charons to fuck off forever"
And fuck off he did. It is possible I screwed something up, and it's also possible that the pirates are underdeveloped when it comes to the whole gathering antiquated junk exercise (it would even make sense, why would the pirates be interested, after all). But it was an abrupt and unceremonious end to the main questline of the expansion.
I still liked it overall. There are many things not to like about it, like the locust swarms, the copypasta Lemurian facilities and the poor encounter design in general. Only the natives were interesting to fight, the strongmen and crabs were snoozefests. They would have been much worse snoozefests if throwing spears hadn't been in the game and I had had to rely on piddling damage from throwing knives and grenades, but they are, and they twoshot everything - a step down from oneshotting everything like they do in the base game, but that's OK. The fact is that even the less inspired dungeons in Underrail are still extra-concentrated RPG exploration crack injected directly into the eyeballs.
Aegis vs pirates was a cool central conflict, and I enjoyed that the expansion forces you to make a hard choice about them. The pirates require you to demonstrate that you're prepared to fuck over Aegis before they'll let you join. I was also impressed by the unique pirate content. Sure it's not a massive chain of quests, but the raids and the assault on the Rig were fun and a nice segway back into the main game. To be honest I was expecting a much more Heart of Darkness kind of vibe from the expansion than Yarr Matey Shiver me Timbers simulator, but maybe you get that if you stick with Aegis. I'll find out next time.
I've read through some of this thread, and it seems I missed a whole bunch of stuff related to Yngwar, the Ferryman, the native village and the monoliths. I figured as much, but it didn't feel as though I had cut myself off from crucial info. Just running the fuck away from the Abyssal station after grabbing the Acorn was cathartic enough. Leaving anything more as a hidden quest/easter egg was the right move, and I'm glad Styg & co weren't afraid of doing that.
Overall I thought Expedition was a slam dunk in a good sense. There's nothing that reaches the quality of the best the main game has to offer, but mostly it's good solid Underrail action. The main thing that strikes me after doing the expansion (and discovering the waterways and realising how much was added even outside of the Black Sea) is how ridiculously huge this game has become. There's an absolutely comical amount of content, which puts most RPGs ever made to shame - indie or otherwise. On the one hand I love it, on the other my character is already level 25 and hasn't even been to Rail Crossing.
TLDR I rate the expansion 7 strongmen out of 100000000000 locusts, spear OP, psi crabs can kiss my ass.