I have already put about 100 hours into Rimworld and even if development ceased today, I would have gotten my money's worth.
That said, I don't think Rimworld is complete. It needs more variety when it comes to challenges. Right now, it is a tower defense game to a large extent. Diseases and upcoming temperature changes are exactly the direction I want the game to move in. That, and more varied goals for raiders (e.g., they should try to destroy your power supplies or steal your food, not charge blindly).
That said, I don't think Rimworld is complete. It needs more variety when it comes to challenges. Right now, it is a tower defense game to a large extent. Diseases and upcoming temperature changes are exactly the direction I want the game to move in. That, and more varied goals for raiders (e.g., they should try to destroy your power supplies or steal your food, not charge blindly).