A gaming system, and method of controlling a gaming system, having a touchscreen, that simulates a game of skill by showing a graphical object and detecting a pair of spaced-apart user input touch points on the touchscreen. An increase in distance between the touch points corresponds to an increase in stress upon the object, which is animated on the touchscreen, and scaling of an associated reward. A failure threshold is selected and the increase in stress is tested against the failure threshold. The failure threshold may be at least partly randomized. If the stress exceeds the threshold, then a failure event is shown. If the touch input ceases, the user may elect to accept then current reward value or to continue. The object may be a bubble and the stress may be expansion of the bubble, leading to popping of the bubble if the expansion exceeds the failure threshold.