Just tried it out, it's really good! My initial gripe was "too easy" since my first run was over a half hour, but world levels can make up for that. I'd like to see more reasons to use the normal melee attack, as you can make a ranged build and just forget about it so far, but I see some talents that make it important so maybe you're already on that. I may not understand the level up system. I see you can reroll all 4, but I think it would be better if you could pick which of the 4 you get at first and then reroll the ones you don't want, at a higher cost. Maybe even make the skills cost more, after 1 or 2 levels I can pick all 4 every time, I think it would be better to force more specialization.
These are just some ideas. All in all, I'd say you're onto something here! The game is good from the demo, and it may be great by full release! I may revisit the comments here after I mess around with it more.