So I got through the opening and built the first phase of the space elevator and loaded the first shipment on to that which unlocks tiers 3 and 4 of crafting research.
The big glaring hole for me right now is there is literally no challenge. Some trivial mobs run around, no big deal, the hardest part of the early game is taking a few minutes to harvest wood and convert it to energy.
This game is Factorio meets Subnautica, with a graphical look somewhat reflecting No Man's Sky. I think they need to certainly emulate Factorio's bug spawning zones that send enemies to attack your structures, or something. Something to add a challenge. Maybe that's in the works and just isn't implemented yet for early access, but that lack of any real challenge makes me concerned for long term replayability.
And they're going to have to add that well, not just throw in stupid things that charge you all day and night like minecraft. Something that comes in waves and progresses intelligently, enemies with abilities. Boss mobs that attack. SOMETHING.
Otherwise though, the constructing loop/core gameplay loop is engaging, the performance is really solid for an early access title and yeah. I'm impressed.