roguelike as a term has ceased to have much meaning but:
- using randomized content to force you to work the game’s rules systematically rather than memorizing specific patterns
- character growth focused on acquisition and consumption of resources rather than pure stats alone
- death causing a restart, emphasizing that the entire game is to be done in one go
many modern rogue"lite" games, such as Rogue Legacy, are designed to be beaten on multiple playthroughs, where you progressively unlock things. these are not to be confused with proper roguelikes.
necrodancer is probably the best modernized example of a roguelike that maintains a lot of what makes the genre compelling without sacrificing it in the name of more traditional rpg unlocking loops. it is not just designed to be played in a single run, it is heavily tuned towards items emphasizing speed vs safety vs “well, this dropped and i hate it but i’m going to use it because i’d be stupid not to,” making it ideal for as a game for multiple playstyles.
a poorly made roguelike often fails to give you strong enough tools, or just boils down to racing stat growths vs the enemies.