I may have to disagree here. realistic? The only way you can solve some puzzles in real life is by looking at the outcome, restoring and trying again?

For instance, in kings quest 5, there's LOTS of puzzles where you need a savegame. Like the desert and trying to find the next oasis. You go off in one direction, die, restore and try another direction. There's the dependancy on save games.
Or feeding the food to the wolf. If you use the pie, you can't solve a later puzzle. but if you don't have the meat, what else are you supposed to use? Of course, they don't have any hints that you did the wrong thing and who goes "of course, I need to use the pie to get rid of this yeti"
Of course, there are some games designed around savegames and I believe Max Payne was one of them. saving/restoring doesn't take much time at all and you can spend ages restoring to the same section over and over, trying to lose less health and look cooler by diving everywhere.
- Nick