Is there anyone that has played enough to judge whether it is worth half off now? I would buy and return it but I have a feeling it would take more than 2 hours to figure it out.
When the original launched, I would be comfortable telling you that within 2 hours you would have seen most of the game. You would get better multi tools and the likes, but it was always the same. Land on a world, extract resources, go to new and world would respawn making it so you were never there. Your teraforming would be gone, no trace of what you did, no other players, alone in a galaxy with no goal except keep going as a nomad towards the centre. I didn't last past 7 hours, as by that time, all planets started to look a like.
In 2 hours now, the tutorial is a bit different, but still somewhat similar to the launch version in what you do. However, it appears to have a lot more under the hood.
My take on playing it a bit over 2 hours yesterday. Started a new game on survival, which will cause additional time to progress, since you will have to constantly take care of your shields. Backtracking into caves, your ship, or use resources to maintain it. You also get less resources in that mode. I also restarted around 20 times to see if I could spawn without hazards on my first planet, and you can't. On survival you will always start on a hazard planet. Can vary what hazard and to which degree, but you will always start with low shields and them being drained. You then have less than 5 minutes before you die unless you get resources (you respawn with a full shield though).
That said, compared to the original launch, you can see there is more to do as you go. You are introduced to building utilities that weren't there before. Processing materials into other materials. Blueprints are done differently. The navigation and adding locations on the planet are more interesting as well. Having to build a utility that extends your scanning ability, putting it on the ground and inserting various pieces. On the first planet the first travels will also be dangerous in a way due to the hazards. The menu shows me I can build vehicles to do on world travel. There are buildings and freighters. I left the first planet and got hostile scans and was almost attacked by space pirates (not a thing I ever experienced at launch).
There is a lot more to the game now than what it had before.
If you are interested, buy it now at 50% off. Because if the reviews from this "next" version comes out and it is somewhat vindicated from launch (actually having the content it promised), it will probably be a while until a new sale since summer sale is already done.
Tl;dr
2 hours now seems to scratch the surface. 2 hours before would show you nearly all there was.