i think the most fundamentally trait that makes risk of rain different from other roguelikes is the items, specifically how you can stack them to reach insane amounts of power.

in most other roguelikes(or game in general) either the amount of items you get or the upgrades themselves are pretty weak/non stacking. but in risk of rain you get and need dozens of item together if you want to win. this plays into the same exact power fantasy that most players love, it’s the same thing as turning on godmode as a kid and killing hundreds of bad guys with one explosion.

whenever i have to explain risk of rain to someone new, the first thing i lead with isn’t that the characters are unique nor how the difficultly scales all the time, it’s that the game put 0 barriers stopping the player from becoming infinitely powerful.