It might be worth mentioning that a sci-fi RTS Meridian: New World and a sf first-person adventure game Albedo: Eyes from Outer Space are part of this weeks Humble Weekly Bundle (both are DRM-Free).

never got to far into the game, but that game had a different vibe didn't find in any other space sim game,

This reminded me how awesome Klingon Academy was. Slower paced than Tie Fighter & co and more strategic, but still similarly challenging and fun. You could target specific subsystems (outgunned and outnumbered? blow the warp engines of the closest ship, warp out & repair, then face them one by one). You could use the battlefield to your own advantage (like hiding in a gas giant; blowing up shield generators and letting the crew die from radiations as you let them stranded near a sun; using asteroids for cover). I don't remember any other space sim that let you do that.

I still have the cds somewhere, unfortunately it doesn't work well on modern systems.

I`m pretty sure some people already worked on a solution for this.

[mysterious music and echovoice] The internet will have the answers my son. Lol

Yeah, they did. I have had this bootmarked since 2012. I just couldn't be bothered to see if it works, yet. >_>

Well, I`m really tempted to buy Space Ranger HD or The Last Federation but I really dislke that ancient 2D-Spacefight. I mean its not even isometric., and SPACE and 2D... meh

Yeah, Khan really got screwed over by that...

One of the good things with the high attention Star Citizen got back on science fiction space games is that there are hopefully a lot of follow-up titles revitalising the genre.

Like this recently founded very promising Kickstarter title (GOG release highly likely in the future): Everspace
https://www.kickstarter.com/projects/rockfishgames/everspace/

It looks and sounds absolutely awesome. Single player story driven space fighter action. I wish them success for the development and look forward when the game comes to GOG.

By the way, why is Galaxy on Fire not on GOG?

Wasteland 2
Xenoblade series
Fallout 3 and New Vegas
Galactic Civilizations II and III
Transistor
The Swapper
Risk of Rain
Xenonauts
STALKER series
Steamworld Dig
Machinarium
Astebreed
Crimzon Clover
Civilization: Beyond Earth
A New Beginning
Supreme Commander
Metroid Prime 3
FTL
Gemini Rue
Primordia
Teslagrad
Unmechanical
To the Moon
Freedom Planet
Infested Planet
Satellite Reign
Shadowrun Returns
Portal 1 and 2

That's exactly what I'm hoping it will be. :D I appreciate that it's probably not going to appeal to those who insist every game has a strong story arc, but as much as I like strong story arcs, I like sandboxes too.

I do too and I would think far more highly if the devs just said that this is what they want to achieve.
The problem is that I don't trust them to deliver an exploration game or a sandbox that are good enough.

I doubt it will be a good exploration game because in their trailers and game-play videos everything looked the same and not scientific enough even for that sort of SF. For me, it won't be enough if a planet has a different colour than another one. ;)
I want space to be overwhelming, dangerous and alien - I'd love to have moments where you are in huge danger and I'd like to feel powerless when facing a threat like a black hole. (The only thing that had me hooked about No Man's Sky was that giant worm in one trailer.)

The reason why I doubt that it will be a good sandbox game is that they have given me no reason to assume that I have a lot of choice what to do. Couldn't they come up with something better than shooting rocks and gathering data about life forms that resemble earth's far too much?
I could imagine myself having fun with upgrading my ship and setting out to the more alien environments near the centre of the galaxy. But what the devs say doesn't sound very good to me.
I assume that if it is fun at all it probably will get old very soon. :)

Hmm.... I'm being a bit more optimistic. I'm putting their banal, crap promotion of the game down to the fact that this game has gone stratospheric since the first gameplay video was uploaded. If they really had to try to sell this thing then we'd probably have seen some much more intense content.

If you're right that would be better for every one. :)
My optimism is completely concentrated on Limit Theory because by now I need a lot of optimism to not give it up.

Limit Theory promises even more than No Man's Sky and we've seen even less of it. It would be one hell of a game if they can pull off half of what they're promising.