Progressed smoothly in a game while not paying attention
My interpretation of this question is that you are asking about divided attention. Some (normally easy) tasks can continue to be accomplished in conditions of divided attention, and with practice you should be able to control this.

I don't know of any research confirming your suggestion that you actually got better in such conditions. You could also look at recent studies on mind-wandering (which tend to show interruptions in the main task when you are thinking about something else) or the passive/active mode in visual tasks (in which, some argue, people actually get better when they don't concentrate as hard).