In a perplexing design decision, there is no way to pause Demon's Souls. Pressing the start button brings up your game menu, but the action continues in the background.
That is odd.
It keeps things tense and realistic in the heat of battle. And it is not too much of an issue because of how the game is designed. If you are in an area where there are no enemies, you don't really need to worry about getting attacked, since enemies don't just wander around the levels (as far as I can tell), they stick to their general locations. So, if you need to go to the restroom, as long as you've cleared the room of enemies, feel free to leave your character standing there and go.
However, there are times when you just need to pause the game. If you are in battle or fighting a boss, and the phone rings, or someone knocks on your door, or whatever the reason, you should be able to pause the action.
I am assuming the lack of pausing is to prevent "cheating". In this game there is no "retry" option. If you die, you lose all your souls and you respawn at the beginning of the level. If you can make it back to your point of death you can reclaim your souls, no real harm done. BUT, if you die a second time before getting your souls back, you lose them forever. That is tough. And harsh. And one reason why this game is so brilliant and fun. You really do fear death, because you cannot avoid it. If you die, the game saves, and you respawn. No multiple save files that you can upload from 5 minutes before. It really makes you pay for your actions. If you see a far off enemy that looks tough, you really have to think long and hard about going to try and fight him. Because if it kills you, you cannot just load to just before the fight and decide not to engage him.
If you could pause the action, players would be able to pause the game just before they died if they were in a bad spot and things were looking grim, press the PS button, exit the game to the XMB, and they could avoid dying and possibly losing all the souls they had. So, I see why the developer removed the pause option.
But still, like I said, for players that want to play the game legitimately (like me), sometimes I just want to pause the damn game!
They could have done something like with Animal Crossing. If you just abruptly exit Animal Crossing, the game knows this and when you load it up the next time, you get a warning. Keep doing it and you get penalized. Sure, that sucks if you have a lot of power outages, but I'm just thinking out loud here. I want a pause button!!!
Anyway, small gripe to a brilliant game.