When the Hero runs past the shop the items will sell, it appears after killing 3 bosses.
In the bottom left if you hover over an item it will show the stats of the item, We currently have 4 tiers based on colours, however, we have not balanced the game as of yet, it was more a prototype of the concept.
I haven't uploaded a desktop version, I'm not sure if I can now but I will look at doing that later on.
Thank you for the feedback.