Just played the demo and loved a lot of what is in there! The procedural cave system is great to explore. I can't wait for this concept to be expanded with more area types (forests, castles, underground, cities, etc)
I did not encounter any sort of bug in the 10 minute time limit.
I did feel the game play got stale after some time (i played it twice). There needs to be something more to the combat to add variety. I understand you only have 1 enemy type but regardless of that, the player controlled unit needs more. More weapon types, more attack options (heavy / light), or some way to control the angle of the swipe (maybe a low, mid, high attack). Something like that could really help diversify the game play and keep it interesting for more than a 10 minute rouge-like expericence.
With that being said, i think you have something great here and i can't wait to see what more development time will produce! Keep up the good work!