120hz mini-games - its an offline game collection, that was developed for android smartphones, that supports high screen refresh rate 90-120 Hertz(hz) screen refresh rate or more. It also support standart 60hz, so it works awsome on every phone, but on 90-120hz (fps) phones a little bit better.
What Hertz (hz) is? In our case, hz - is amount of image refreshes on your display in 1 second (1000ms). Its almost the same as fps (Frames per second). The more refreshes happens, the smoother and sharper everything looks on your display.