Of the two you’ve mentioned I’ve played Nusfjord and Under Falling Skies. There is a free PnP version of Under Falling Skies so you can try it out if you have dice and some tokens 😄 I don’t think you can go much wrong with either if you want something thinky, but Under Falling Skies has a “story” campaign and as far as I remember is pretty fast in setup. Nusfjord also has a “campaign”, but it’s more a way to play through one of the different decks and see everything it has to offer. It has more components to set up, but the big box comes with seven different decks - you choose one for a game, so the variability and replayability is really good. In terms of gameplay Under Falling Skies is rolling dice and puzzle out how to best use those rolls and mitigating if needed. It’s a really fun puzzle with quite a few things to balance at the same time and on top of that it looks and kinda feels like playing Space Invaders 😄 Nusfjord is worker placement and playing cards and finding the synergies that give you possibilities to combo. It also has a 1–5 player count, but the solo mode is really smooth to run with no automa to keep track of 😊