Thank you for your comment and all yours great ideas ! I didn't think about put a mecanic during overheat because I wanted player manage with their tools at the same time, but it's a cool idea to add gameplay to reduce faster overheat !
I note yours feedbacks down for an updated version of my game, especially for put graphics cool downs more impacting and bug (use tools had to decrease number of bar on the left bottom corner, number in the HUD indicates numbers of charged needed to launch tools) :).