>Why can't you play more than one game

Because if you could in this example it wouldn't make sense, because you could play one of the dozens of mario games, but you cannot play a dozen different of many other games, so to make the example fair you'd have to pick one. But that was just for the examples sake, obviously you can play more than 1 game I general, but in this case I personally want a game I can play for long periods of time and always have new stuff to work towards. In most games you hit a wall where your options are either repeat doing the same thing over and over, start over from scratch, or put self proclaimed rules on it to make it interesting. I'm just trying to weed out what games i might not of heard of that don't fall into Ant od those 3 categories, where you can keep playing the same game and not easily run out of content as the Endgame is full of stuff to grind and new content is added regularly so unless you no life it you won't find yourself out of content