A lot of people have covered this topic before. I’m more doing this to pin the idea down in case it comes up in conversation again, than because it’s something that really needs to be discussed.
Souls-like is a subgenre of Action RPG games, formed by the unique conventions of Demon’s/Dark Souls. Similar to a roguelike, the Souls series of games have come up with a number of unique conventions that many other games have taken some degree of inspiration from. Games that follow enough of these conventions can be called Souls-Like. Some of them are more influential than others.
- Collecting a currency that is lost on death, but stored at the place where you died, and erased when you die again.
- There are standard action RPG trappings: levels, equipment, consumable items,
- The player’s standard attacks have a startup of about half a second or longer (30f at 60fps)
- Players and enemies can have their attacks interrupted by hitstun.
- All combat actions (attacking, dodging, blocking, running, parrying) are rationed through a shared stamina bar.
- Attacks have actual hitboxes during their animations, not paired animations.
- There is a dodge and block ability.
- Other players can invade your single player session to try to kill you in PVP
- Using checkpoints resets your health, healing items, and the enemies in the level, but don’t reset items collected or changes to the level’s state.
- Level design based on checkpoints and opening up shortcuts to earlier checkpoints.
- Spells, items, and other actions have associated animations that can be interrupted by hitstun before they take effect.
- Other players can join you to cooperate in beating levels.
- The actions of other players on the network can have an effect on your local session, such as leaving messages behind.
- You can warp between checkpoints.
- Some moves have super armor, or there is a poise system that confers armor
- No pausing, except at checkpoints
- The controller convention of having attacks and blocking on the shoulder buttons, and item management on the Dpad.
- Having a classless RPG system, where the only differentiation between characters is their stats and equipment, no fundamental new abilities, or permanent bonuses.
- Having a metroidvania style interconnected world that becomes more interconnected over time.
- There aren’t many cutscenes, or canned animations.
- The setting of a kingdom that was once great, but some calamity connected to the main plot befell it, and now you’re wandering through its corrupted remains.
- NPCs that all have a sinister chuckle.
- The game is hard.