I think you've set up a bunch of mechanics here that operate together really well! The UI and menu system is nice and clean and clearly something you devoted attention to so that players had visibility of the inner workings of the game's stat-based mechanics. All the stats flow nicely, there's immediate visual feedback from the UI, attacking and defending, and the experience system's effects when levelling. It's an enormous achievement to have a class and stat based RPG lurking within the guise of a traditional roguelike, and I was surprised at the inclusion of merchants and item-based rewards that provide a little something more than the conventional roguelike concept. Feels like you could easily branch this out with more time given there's no end of things to customise.
For constructive feedback - hmm - if you're going for a Diablo style dungeon-crawler the sense of incremental progression and a gameplay loop could be worked on a bit. There's a tension between the pretty generous recovery system and having a bed to rest in the central hub. Same with the coin rewards and cheap as chips vendors. As you know, a lot of Diablo's addictiveness is its exquisitely-balanced rewards and upgrades system that is scaled perfectly to the ever-increasing difficulty of its dungeons. It can take years to design a game using randomness that offers unpredictability but also feels fair and constantly progressive. I think you're on the right step to conjuring a little bit of that magic through your design.
Great work. Oh, and I'll have to check out DiabloRL!