Pretty good, but also pretty boring.

Early game Core Keeper is fun. You mine for ore, run away from enemies because you're too weak to fight them, and then eventually get good enough armour and weapons.

Then you venture out to the next area. You mine for ore, run away from enemies because you're too weak to fight them, and then eventually get good enough armour and weapons.

And repeat.

Not to say it isn't fun, it's just that this structure gets boring after a while. There are bosses, but they seem to be extremely hard compared to what weapons you currently have. (or maybe I'm just bad, who knows)

Do take this with a grain of salt though, as the game is still in early access, so my issues may be addressed in the future.

Worth a purchase, but probably only on sale.