I decided to pick up this title after watching a Let's Play of it, and liking what I saw. Space Engineers had been interesting to learn, but its a bit of a sterile experience in single player. I figured it would be Space Engineers+. While I've only played about twelve hours of the game so far, I would say it's more of a combination of the Space Engineers, Subnautica, and No Man's Sky... with a bit of Kerbal Space Program and Minecraft thrown into the mix. Keep in mind, I started a quick game at the easy difficulty, because I wanted to learn the mechanics without the ever present fear of death thrown into the mix.
The star of the show in my opinion are the build options. You have a lot of options to choose from when building things, from power generators and fuel sources, to different types of controls, equipment, defenses, and weapons. One interesting aspect of building ships and bases are your computer-based resources. Each ship and base has a "core" with a processor, which can only handle so much equipment installed. The more "smarts" equipment requires, the more computer power is required to operate it. Naturally, additional computers can be added to expand resources.
Also, unlike Space Engineers, thruster placement matters. Your ships have a center of mass that can change with their load, and this can change their performance in flight. If you've ever had a ship in KSP suddenly lose control in flight, thanks to a changing center of mass, you'll know what I'm talking about. Thankfully, there's a "center of mass" overlay option, as well as other options like "airtight."
Finally, you have a ton of building block variants to work with, ranging from full cubes, to the smallest partial blocks. There's literally hundreds to choose from. Not to mention how many options you have to change the texture, color, and decal on the surface of a block using the re-texturing tool. Not the entire block, mind you, just one of its surfaces. So you can have one texture and color on one side, and have a completely different texture and color on the other side!
Next up is the rest of the game play. This is a survival game, which means not only managing your hunger, health, stamina, oxygen, and body temperature, but also gathering the raw materials you need to build tools, equipment, weapons, and structures. Unlike other survival games I've played, you don't need to tell your assemblers to build individual components. As long as you have the raw materials in your inventory, they will build what you need to build what you want. Water is a resource in the game, but thirst isn't a factor that comes into play. Sleep isn't required as far as I can tell, but night is dark enough for me to want to sleep anyways. It's also a great way to advance the clock on projects being built in your assemblers or plants growing in your garden, at the cost of hunger, of course.
Combat is rather nuanced IMO. Yes, you do have a hit-point pool, but there are also many types, and degrees, of wounds. Some might require a simple bandage. Others can be treated with the various types of plants that grow in the area. Depending upon how severe an injury is, medicines, "trauma kits," or even stepping into fully automatic medical device might be required. Oh, and left untreated, a wound will get worse.
There are tutorial missions you can run, "story" missions that are available, and other missions are offered as well. All of these are optional, thankfully, though you do get some bonuses from doing the tutorial missions. There's also an "encyclopedia" on your PDA, which describes a lot of the game's mechanics. Combined with the mouse-over hints in the various interfaces, I found it was fairly easy to figure out what I needed to do in the game. Which is a good thing, because the two wikis I found are woefully out of date.
From what I can see, while there are preset difficulty levels (easy, normal, hard), there's a wide variety of options to choose from, so you can tailor your experience in the game to best suit you.
Next, we've got the environment itself. I've only seen the "earthlike" planet so far, but it has a wide range of flora and fauna, with many biomes on its surface. There are also sapient beings living on it. There's multiple factions that you can build (or ruin) your reputation with. Some of the creatures are quite alien. Some are a little bit familiar, which provide hints about the story running in the background. Some are hostile, some are peaceful, some are rather skittish, and some can be provoked if you're not careful. Behaviors range from solo charges, to pack-like behavior, where some of the pack try to flank you while your attention is elsewhere.
Oh, and the weather! Can't forget the weather! Sunny days, cloudy and windy. Rain and storms. Temperature variations, so a hot or cool beverage might hit the spot. Because of the weather, there's no guarantee that solar panels will provide all the energy you need, so you better have a backup generator or two, just in case.
The worlds themselves seem very small, and there are no orbital mechanics to speak of. The planet I'm on supposedly has a moon, but I've never seen it. The first thing I did at night was look at the stars, which are definitely fixed in place. It seems we've got another game where the stars in the sky are fixed into a sphere, the planets are suspended in the middle, with the sun rolling along its circumstance. It's a minor quibble, given how fantastic the game is otherwise, but these kinds of celestial mechanics really belong in a fantasy game, not a space game.
Finally, there are the visuals. This game looks good in my opinion, and runs rather smoothly on ultra-graphics settings, on my old GTX 980:
The star of the show in my opinion are the build options. You have a lot of options to choose from when building things, from power generators and fuel sources, to different types of controls, equipment, defenses, and weapons. One interesting aspect of building ships and bases are your computer-based resources. Each ship and base has a "core" with a processor, which can only handle so much equipment installed. The more "smarts" equipment requires, the more computer power is required to operate it. Naturally, additional computers can be added to expand resources.
Also, unlike Space Engineers, thruster placement matters. Your ships have a center of mass that can change with their load, and this can change their performance in flight. If you've ever had a ship in KSP suddenly lose control in flight, thanks to a changing center of mass, you'll know what I'm talking about. Thankfully, there's a "center of mass" overlay option, as well as other options like "airtight."
Finally, you have a ton of building block variants to work with, ranging from full cubes, to the smallest partial blocks. There's literally hundreds to choose from. Not to mention how many options you have to change the texture, color, and decal on the surface of a block using the re-texturing tool. Not the entire block, mind you, just one of its surfaces. So you can have one texture and color on one side, and have a completely different texture and color on the other side!
Next up is the rest of the game play. This is a survival game, which means not only managing your hunger, health, stamina, oxygen, and body temperature, but also gathering the raw materials you need to build tools, equipment, weapons, and structures. Unlike other survival games I've played, you don't need to tell your assemblers to build individual components. As long as you have the raw materials in your inventory, they will build what you need to build what you want. Water is a resource in the game, but thirst isn't a factor that comes into play. Sleep isn't required as far as I can tell, but night is dark enough for me to want to sleep anyways. It's also a great way to advance the clock on projects being built in your assemblers or plants growing in your garden, at the cost of hunger, of course.
Combat is rather nuanced IMO. Yes, you do have a hit-point pool, but there are also many types, and degrees, of wounds. Some might require a simple bandage. Others can be treated with the various types of plants that grow in the area. Depending upon how severe an injury is, medicines, "trauma kits," or even stepping into fully automatic medical device might be required. Oh, and left untreated, a wound will get worse.
There are tutorial missions you can run, "story" missions that are available, and other missions are offered as well. All of these are optional, thankfully, though you do get some bonuses from doing the tutorial missions. There's also an "encyclopedia" on your PDA, which describes a lot of the game's mechanics. Combined with the mouse-over hints in the various interfaces, I found it was fairly easy to figure out what I needed to do in the game. Which is a good thing, because the two wikis I found are woefully out of date.
From what I can see, while there are preset difficulty levels (easy, normal, hard), there's a wide variety of options to choose from, so you can tailor your experience in the game to best suit you.
Next, we've got the environment itself. I've only seen the "earthlike" planet so far, but it has a wide range of flora and fauna, with many biomes on its surface. There are also sapient beings living on it. There's multiple factions that you can build (or ruin) your reputation with. Some of the creatures are quite alien. Some are a little bit familiar, which provide hints about the story running in the background. Some are hostile, some are peaceful, some are rather skittish, and some can be provoked if you're not careful. Behaviors range from solo charges, to pack-like behavior, where some of the pack try to flank you while your attention is elsewhere.
Oh, and the weather! Can't forget the weather! Sunny days, cloudy and windy. Rain and storms. Temperature variations, so a hot or cool beverage might hit the spot. Because of the weather, there's no guarantee that solar panels will provide all the energy you need, so you better have a backup generator or two, just in case.
The worlds themselves seem very small, and there are no orbital mechanics to speak of. The planet I'm on supposedly has a moon, but I've never seen it. The first thing I did at night was look at the stars, which are definitely fixed in place. It seems we've got another game where the stars in the sky are fixed into a sphere, the planets are suspended in the middle, with the sun rolling along its circumstance. It's a minor quibble, given how fantastic the game is otherwise, but these kinds of celestial mechanics really belong in a fantasy game, not a space game.

Finally, there are the visuals. This game looks good in my opinion, and runs rather smoothly on ultra-graphics settings, on my old GTX 980: