Scratch

Unfortunately you can't. 

There are things you can do, though. You could make a password system where you enter a password and it takes you somewhere. On other (but slightly complicated) way is to make the user download the project, and not make the game reset when you press the green flag. Whenever the user wants to save, they just press the "Save" button at the top to save the project, then when they return the data will still be there.

Andresmh recently announced that there could be a more online version of Scratch, sort of like NetScratch, and that included possibly a way to save your games online. But these were just suggestions, so don't expect it. Just use the ways mentioned by hmnwilson.

Locomule wrote:

You can go old school...
Decide on a minimum amount of variables that would constitute a Save in your game. The less variables needed the easier this is to do, by the way. Anyway, lets say we wanted to Save...
position
health
current level
for a total of four variables to Save. Make your game so that when the player uses the Save feature, the game computes the position into two variables (x and y), the health into one variable, and the current level into another. Then it sticks them all together and outputs (says) it to the player on screen. The player writes it down on paper. The next time they start the game, they use the Load option to hand enter the last Save code. The game starts back where they saved it at. If you are worried about people "cheating" via the Save code you can figure out a way to scramble it, maybe with a checksum also. Like everything else on Scratch, this is not a perfect solution to all games but it is a far cry from not being able to continue a game between Scratch sessions, in my opinion.

Zoomreddin wrote:

Ok I'll try that!
I'll try that I think that's what I need! Thank-you.