We made a game called Dead Cells, which we define as a "Roguevania" (ie. a mix between Castlevania™ type games & roguelikes, with a modern approach). We were actually really surprised by the overwhelmingly positive reviews and feedback from the gaming community and press. But, as a pragmatic developer and game-designer, I don't believe in random success and unpredictable stuff. So I tried to understand and analyse what worked for us, with reproducibility in mind. So, let's talk about "core-loops", among other things.