This is really cool. Awhile back I saw a mobile game with a really similar concept to this and your execution is great!
I would love to see you add different gear, perhaps active items you can use in battle, and more environments!
I think one thing you could change is the dice number display. Instead of displaying that on the button maybe somewhere more visible or some pop-up indicator on the screen to make it more clear what number you got.
Overall great job :D