In essence, Spiritfarer plays like a 2-D Raft, where you collect resources through various methods in order to craft facilities and structures for your boat. The system is pretty simple and intuitive, and you can place buildings anywhere within your boat’s space, since it’ll auto-construct ladders. The tricky part, especially early-game, is wrestling with the boat’s size. The various facilities come in wild shapes and sizes, and it’s as fun as it is frustrating to try and clutter it all together. Fortunately, there is an edit feature where you can freely move the buildings without having to dismantle and rebuild them.
There’s also plenty of upgrades for your rig. You can go to Al’s Shipyard to increase the boat’s size, unlock new facilities, and a host of other things. One of the best aspects of this is that your quest menu will actually list the next upgrades, showing you what you need without having to go to Al’s just because you forgot what was required. You can also upgrade individual facilities, but you need to unlock those upgrades as they come. Stella herself also has upgrades. You earn Obols as payment from newly welcomed spirits, and by donating those to various shrines found throughout the world, you can give her improved mobility and whatnot.
So how do you get resources? Well, the main way is to visit various islands. Your map starts out pretty small, but expands as you explore further. And while you could theoretically shoot in the dark for a new island (especially on repeat playthroughs if you know where they are), you can also receive quests and random messages in a bottle that will mark out those otherwise darkened areas. Once you start getting new facilities, you can kill the long sailing times by doing tasks (more on that later), fishing, or just straight-up relaxing. The ship cannot move at night, but that can be remedied by going to bed. Just remember to ring the bell just outside of your room to wake your guests (and also remember to never ring it unless the time display on the HUD has the bell symbol, especially not while they’re supposed to be asleep).