Explore, build stuff, craft gear and farm and hunt for food. Kill the boss of whichever biome you're in, then move up to the next one for more upgrades. There are currently five playable biomes with three more in development. Development is slow, but the devs focus on bug smashing, so it runs pretty smoothly. Map is procedural, so each playthrough is a little different and some maps are easier than others. There's a website that can show you your map if you type in the seed. Mods exist outside of steam and can fix most of the things you might complain about.