So after a few days of playing, I've reached a conclusion about the game:
It's very gamey, and progression isn't well thought out.
First, covering the construction aspects, which should be the biggest concern for a game like this.
The tier progression forces you deeper into space, constantly. It takes 1,000 fuel to move to a new sector, so if you ever want to backtrack, it's going to cost you 2,000 fuel to go back to your home base and then go back to the useful areas again. This effectively forces you to keep moving forward, as you cannot simply pop back home to pick up some supplies or anything.
Since you keep moving, there's a real virtue AGAINST permanent structures. Even in local space, anything larger than a dirt hole with a bed and temporary storage is overkill. And even then, it's a lot simpler to beam back to your ship, rather than go to your planetary basecamp to rest. Not that your structures would be any good even if you spent time on them. Wood, dirt, and cobblestone are the only truly readily abundant materials, metal blocks are possible, but only for certain types of metal, and only at extremely high cost. Structures end up made from wood or stone, or just being dug into the ground. Fancier materials do exist, namely in Apex or Glitch areas, where you can mine into the structure itself to recover fancy blocks, but you can't craft them, and you have to brave the dungeon-like area to get them. So when you finally DO loot enough nice material to build something, you end up abandoning the planet anyways.
So as much as the dev screenshots show fancy buildings, gorgeous terrain, and theme decorations, it's only ever stuff you stumble across, not something a player should ever actually build.
Second is the combat, which is the other big thing this game has going for it. Controls seem to be fine, except for the limited arc available on some weapons, and weird situations like the Terraria "slime is sitting 1 block below me on a ramp, my sword can't swing low enough but it can still touch me" issues. There's a decent spread of crafted weapons, which are all decent, but looted gear is generally always garbage.
The problem with combat, is the AP system. Armor Penetration. As detailed previously in the thread, armor penetration is effectively a multiplier to the damage you deal, while armor divides your damage. The result of this is that higher penetration is ALWAYS higher damage, and that after a certain point, armor becomes completely ineffective against certain levels of penetration. What this means for the game, is that enemies scale with their difficulty level, raising their armor and their penetration, and that it quickly becomes extremely difficult to damage many enemies, while they can totally ignore your armor. Higher level enemies simply become broken. It's not even an issue of skill, it's a matter of 'they can kill you in one hit, while you have to deal 20 hits' that simply makes combat impossible. A better strategy than fighting, is to simply have a lot of dirt, and throw it around yourself when a monster approaches, then encase the monster, dig yourself free, and continue, leaving it behind.
Bosses are worse in this respect. The only way to really combat them is cheese.
Third problem I have is the tiers. I like the idea of a game with progression, from one area to the next, so there's not everyone overpowered along with all the newbies all in the same area. Since Starbound allows for multiple planets, you can allow older players to venture forth to more difficult areas. The problem is how meta the tier system is. To craft steel armor, you have to get enough steel, and gold armor. Gold armor requires its own stack of gold ingots. This makes no real sense, and gets into game-crafting areas. The only reason that gold is requires, is to make it more difficult to obtain. Steel armor shouldn't be layered over gold. It's only there to force progression, and it does so poorly. Gold armor is worse than iron/silver of the previous tier, so to obtain steel armor, you must craft a set of gold for the express purpose of sitting in your inventory until you get enough steel.
A lot of useful items are untiered, as well. Being unable to craft guns relies on you finding them, from chests or merchants, which are 99% rubbish because they have low armor penetration value and, as above, that makes them useless. Hunting knives and shields are also very useful, but only tier 1, becoming useless after defeating the UFO because they simply don't do enough damage or block anything.
The end result, if you ask me, is that the game is too focused on progression. It pushes you further into space, abandoning old bases, figuring out why you need certain materials, and just popping up and down from your ship instead of handling real construction.
What I would do: Nerf or remove the armor penetration system, put a cooldown on beaming to and from ship, reduce fuel costs for moving places considerably (especially to places you've already been!), rework crafting requirements to get rid of illogical crafting, and allow more fancy building blocks to be crafted by the player. Also make the ship MUCH bigger.