I was excited until I read "rogue-like". Jeez. How is that not a "modern" system? It would be nice to have games like this one with actual level design and actual levels.
Actual level design with actual levels are barely possible for one-man-studio. But another attributes are carefully implemented. Various behavior of the enemies, health, armor and ammo management, weapons, which are useful in each playstyle and situation.
Not sure where the conception comes from that rogue-like gameplay is modern. Yes, is has become popular to add rogue-like gameplay elements to your game, probably starting with Spelunky, but they are called rogue-likes because they share gameplay elements with Rogue, which is an RPG from the 80s. Rogue-like games like Hack or NetHack have been around for more than three decades.
Plus, just because levels are procedurally generated doesn't mean that the creator hasn't put a lot of work into the algorithm that generates those levels.