Basically an attempt to reboot the Escape Velocity series made by Ambrosia Software,
Endless Sky is one of those comfy Space Privateering games.
If you've never played stuff like this, its kinda like Elite: Dangerous had a baby with the old Tycoon style games.
You pick a starter ship from 3 broad ship 'types': Passenger, Cargo, and Combat.
From there, the only common goal is to basically fly around the galaxy making money, pay off your starter loan, and get a bigger fleet of ships. Your two states of gameplay are either being planetside, where time stops and everything happens in walls of text, or being in space, where things are 'realtime' -- ships move around the galaxy doing shit, combat can happen, but days only pass when you warp jump to new systems or land on something.
You can do the obvious of being a merchant/cruise ship, privateer for several factions, or a pirate, but the real attraction is visiting the Spaceport (basically a pub) on every planet and getting dragged into random storylines.
Get involved in the war between the Feds and the Free Worlds, discover unknown aliens, do unsanctioned research into ancient human colonies that shouldn't exist, help terraform a planet over a few months, transport a Galactic pop band around several gigs, run drugs, be bait for pirate raids, be bait for nosy Feds, ship materials to the people constructing a legit Ringworld, or just transport a family from one side of known space to the other.
In between all this, you'll be constantly buying, selling, and upgrading ships as your career path changes. Don't wanna trade for a while, feel like going and getting some combat Infamy? Store those ships at a shipyard, buy some interceptors and frigates, and go pirate the pirates for a while. Hell, be fucking silly when you do it: buy a huge Starliner, rip out
everything to do with fancy passengers, and replace the guts with Fighter Bays to hold a literal swarm of tiny attack craft. Ship customization is insane and is half the appeal of the game, at least to me.
Pretty much my only issue with the game is stuff that happens in Storylets
feels inconsequential, because the consequences cant happen planetside: You'll never shit-talk someone in text and then find your ship sabotaged, it usually means an enemy (or their whole fleet) will be waiting in space when you take off again.
They definitely do have consequences, since many stories branch out, some let you enter factions, get special piloting licenses, unlock exclusive outfitters and shipyards, and any other manner of things. In fact the game is quite reactive.
It's one of my favorite "whiskey, podcast and chill" games. It's also FREE.