So, I don't own it on GOG yet, but I got the Early Access on Steam on the first month the game was released.
You have a lot of things to do, that will reward you. You can explore planets to get books and logs and add them to your codex, then read and unravel stories, history and mysteries of places you visited.
You can make stuff, you can get weapons of all kind and cool gadgets to aid you. Crafting system is interesting and there are lots of things to make. You can upgrade your ship and you can really enjoy a sandbox game.
What surprised me was how much they enhanced the game (it was really laggy, they fixed that) and also how great it feels. They also added a scenario. THAT addition was great as a step by step indirect guide - tutorial to the sandbox experience. The bad thing about this, is that people do a huge mistake. They forget that Starbound started as a sandbox game with not any solid concrete scenario at start. Sure you could find books to add to your codex but that's it. And then came pepole that said that the scenario is too small. Well of course, after finishing the scenario you continue to the sandbox experience and that is what I personally was expecting really. If you need a game with huge scenario you better choose another game. That does not really stop the developers to enhance it but version 1 is good enough in my opinion.
Gameplay is okay I guess, you get used to it.
Graphics are beautyful, still simple and neat.
It still keeps me interested as of a replayability value.
It has a lot of things to do.
It might be very irritating though the fact that you lose all your previous saves before V1.
Overall I give it a 4/5, because there is still room for imrovement. I mean, Starbound developers can add some more scenario and conent, fix some (rare) minor technical issues , and overall make it as big as other games are. V1 though deserves those 4 stars, it is decent and I believe some of us were too strict, maybe because of the huge waiting time.