Button Trainer

Select the number of inputs, set the keybinds and press start. Random keys are displayed with an interval between 0.1 and 3 seconds. The goal is to press the displayed key within 2 seconds, but the allotted time gets 5% faster every level. If you press the right key in less than half the allotted time, it gets 25% faster instead. You lose if you take too long or press the wrong key. 

Works with keyboard, mouse, and scroll wheel input. You can make some inputs more frequent than others by duplicating them.