Very interesting idea, I like the idea of having to play two games in tandem with each other like this! Dungeon crawling while deck building seems like it has a lot of potential.
I was a little confused by the numerous different stats and how they affected combat / overall objectives. Maybe some color-coding or icons would have helped with that? It wasn’t clear to me how the positive and negative values affected gameplay in the overworld.
Lastly, I think the turn-based nature of the movement was a bit lost on me - I ended up just clicking through and ending my turn a lot just so I could move around and explore the map. You mentioned that you ran out of time to balance and make the cards more important, so maybe that would have helped make it clear how to actually make the most of a turn instead of just moving around.
Overall though, nice job! I think this is an interesting mechanic and the presentation is pretty nice too!