The moment Starbound really clicked for me I was tunnelling into the center of a planet. I burst through yet another layer of stone, bone, and who knows what else, and I discovered the ruins of an abandoned civilisation. It was made up of… tiny toy houses that seemed to have been terrorised by an apocalyptic robot not much bigger than my character. I made short work of him. It was all so ridiculous and unexpected. Starbound holds the potential to do that millions of times.
Starbound is enormous. Thanks to a procedural planet seeding system, its universe is populated by quadrillions of planets. You explore them in a way reminiscent of other exploration/crafting games like Terraria and Minecraft. Expect tons of tunnelling, construction, base building, weapon and armour crafting, and rudimentary combat. Each planet, though, is like an egg delivered straight from the cloaca of madness. You never know what you'll find when you touch down, let alone when you start digging beneath the forest-laden, frosted, fiery, sandy, boggy, or weird-arse tentacle-strewn surface.
That's not to say Starbound is a truly infinite creation. After playing for nearly 40 hours, I've seen some creatures and biomes repeat, though in different configurations than I'd experienced previously. For a while, though, you probably won't even notice. Starbound is, first and foremost, a game of discovery, and it delivers that in spades.
You can go about this as you please, although you're not able to properly explore the universe and its many planets until you've completed some quests to repair your ship. But you can play Starbound as a casual exploration game, a survival game where you have to cook and eat regularly to survive, a base construction and decoration game, or a quest-based adventure full of combat and bosses. To an extent, many of these aspects will mesh as you play, but once the game opens up after the first couple slightly slow hours, you can pick your focus and change things up as you please.
Starbound's breadth at times verges on extraordinary, but I'm not so enamoured with some of its individual parts. The story is passable, but I never found many strong hooks. Main story quests lead to some fun and varied boss fights, but side quests are of the predictable collect/craft X number of [THING] sort. Combat, on the whole, is basic, button-mashy, and at times, clunky. You're able to craft all these exciting weapons with flashy effects that dole out damage in big numbers, but many of them aren't particularly exciting to, you know, use.
The other big issue is that Starbound is (randomly generated) worlds better as a multiplayer experience than it is single-player. Back when Starbound first launched as an Early Access game, my then-girlfriend and I spent days hunched over our laptops, raiding the techno-Egyptian halls of bizarre bird people and using their ornate decorations to spruce up our in-game living room.
Playing the release version with friends, I found it easy to settle into a similar rhythm. You can go adventure together or each do your own thing and then return to the base you're all building with a treasure trove of loot and bird skulls for the skeleton room meant to serve as a warning to any bird people who might be seeking vengeance. It's freeform fun, with gaps in action or exploration filled in with chatting and laughing.
Doing those things alone is a bit less enjoyable. The game's story and quests offer direction, but there's still a lot of downtime and space in the game's design. Decorating your base, tunnelling (and tunnelling and tunnelling), and hacking away at hundreds of enemies sometimes rings hollow when you're doing it sans pals. The ability to colonise planets and have people join your ship's crew definitely helps, but it doesn't completely alleviate the problem.
I found the game's first couple hours to be especially sloggy when I was on my own, because my gear was crap, and I kept dying when enemies outnumbered me. I was playing on survival mode, which punishes death by leaving most of your crafting supplies on your cold, dead body. The game also doesn't explain much about its crafting system, so upping your arsenal when you're flying solo is kind of a crapshoot. I recommend rolling with friends or seeking help from a wiki.
Starbound is a ride that can alternate between bumpy and (occasionally) boring, but there's a magic to it that makes everything else worthwhile. The universe is just so strange and unpredictable that you can never quite get tired of it. Sure, you might be chopping down yet another tree to craft its wood into timber, but just as your mind starts to wander, you realise the tree is made of fucking cotton candy. Or you're running through the bog near your base and see the friendly frog people you'd begun to take for granted getting attacked by mutant brain apes, and you're like, "NUH-UH, NOT IN MY HOUSE."
Starbound is full of whimsy, surprise, and strange little interactions. It's a universe unto itself, just begging to be explored.