Would be cool to see something to level up grades, for example, we have Grade F stage 50 item, then with some item and a lot of money we can make it Grade E stage 0, then after grading it up to stage 50 we can upgrade it to Grade D and so on. Items for leveling up grades can be dropped from high...
Make it possible to buy more than one generator in stack, there is always not enough space in inventory to have 5xBurst generators and 5xProtect generator plus other generators.