Many free-to-play games are built around the concept of “energy.” They might have different names for it, but the concept is the same. Doing things in the game costs energy, and when you run out of the juice, you’re done playing until that energy bar recharges. Might be an hour. Might be a week. Or, you can swipe the credit card and buy a refill on the spot. Hey! Consider what the energy concept does to the art of game design, when the experience of gaming is constantly interrupted to shove a coin slot in your face. Hookshot has the story.
Back in the olden days, BBSes would offer door games that limited your play in the same way, with turns or actions. This was so you couldn’t dominate the game by playing it 24/7 and grinding to victory. Maybe if the BBS let players buy a fresh sack of turns for a buck, the BBS might have been able to afford more than eight phone lines.