i think the explanation from my experience (though im not sure ) is that when you try playing a game and after finishing a game and you dont close the window and you start the game again the time keeps on clicking and thats why your time play is getting longer.
if you just try playing 1 game on pizzaboy its not really impossible to play in 1 minute and 1- seconds the game is just a short and fast game but when you try to restart the game it gives you a longer time , counting the time from when you started and finished playing and thats not only 1 game - it will be your time playing and restarting the game until your finished.
the game pizza boy doesnt really last 6 minutes it doesnt even last 2 minutes to play so i think your mistaken about - its impossible to play the game in 1 minute and 10 seconds.