Wow- This is great! I just played for a half hour.
I think the ability icons are fantastic and work well. The actual game art I think will limit your potential a bit- if you could get a better tile set and maybe an actual character instead of a ball with an symbol it would work well for you. The gameplay itself is fantastic- easy to get lost in and play for a while. I love the rouge-like elements and the always working towards a more powerful starting setup. Overall great game.
The UI felt a little confusing at times. The line of site was a little frustrating at times too- when a guy was just outside of it shooting at you and you are shooting back but you cant tell what your range is or if you are hitting him or not.
The mining was a fun surprise too- i liked that aspect of the game. you did a lot of work here! the game play is really polished and fluid. Do you eventually get to find different boss types? Progression feels really slow too. I would maybe lower the price of a couple of upgrades to make you feel like you could buy something after the first playthrough or two- i didnt get 1000 gold till a little later when I got a feel for everything.
Also potions I think should show bottom of the screen so you can use them without going into the inventory.
Thats my two cents / First impressions of the game. Overall - I am very impressed I wish you the best of luck and success with it!