It's only an hour or so per run. Maybe shorter like 30 minutes, or longer like two hours, if you make fast/slow decisions. So it's not like Sword of the Stars: The Pit where it takes 20 or 30 hours and your character slowly starves to death.

It's paced like Slay The Spire, but there's a bit of a juggling act. You have three floors of combat and a room where your perma-health takes damage if enemies reach. Enemies only fight a single round of combat before climbing a floor each turn and new waves spawn at the bottom. After all waves are done, you collect cards and relics and resolve some shops and events and do it again, 8 battles total.

Personally, I prefer short-format games when there's permadeath.

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Well, I guess I have to keep playing on Steam for now. GOG Connect would be nice. :(

The term roguelike comes from the eponymous 1980's video game Rogue which was a dungeon crawler. The term originally meant games that are like Rogue, as in dungeon crawlers, but it's since evolved to represent a genre of games.

Modern use generally means the game has permadeath, some sort of progression system, and procedural generation or other means of randomization in story progression or level design. The games are usually more difficult to "win" or complete because the game is saved automatically and death means starting from the beginning, sometimes with some benefit of previous attempts.

In the case of deckbuilding games, your progression is in the cards you add to your deck, more powerful cards, to assist with more powerful enemies that will appear as you progress further, and death (losing the core) results in starting over. Sometimes you can unlock things during previous attempts to make future attempts easier.

In FTL no your first attempt your very unlikely to make it to the end, because certain events can lead to sever losses that can cripple you, and you lack an understanding of strategies and weapons to purchase. As you make multiple attempts you will progress further because the progression is in the the knowledge you earn, knowing the potential outcome of events, better strategizing of routes to pick, knowing what kind of weapons work well together, understanding how to defeat enemies. Death results in starting over from the beginning (there's no reloading a saved game after death), but you can unlock new ships along the way meaning future runs could potentially be more difficult or easier.
This is the best representation of a modern roguelike game.