Phoenix, Kongregate doesn't save to any magical Kongregate server somewhere. It saves to that computer, in a flash player cache file. So yea you won't have a save file on your computer if you saved it on someone else's computer.
The only thing that bugs me about this is the 'perfect score' thing. Once I got the elves I started destroying the tower well before the perfect score mark. Getting mow points for defeating the level earlier would probably be a better idea.
I know my browser doesn't have any sort of weird delete cache settings, I have no problem saving. BUT I play at work and at home, and when I leave work I copy my saved files from the 'cache' folder kongregate creates for all of the games (it's in some sort of flash player folder). I've got protector, amorphous, sonny, etc. in there. But I noticed THIS game does not make a file in there. So yes, if you don't clear your browser cache and your browser doesn't crash, your saved game will be there. Otherwise? It's gone.
Also the game needs to be connected to keep saves, just like badges.
I noticed this game doesn't even create a save file in the cache folders on your computer like the other ones do. Who knows why, but that's definitely why your stuff is gone after you go away from this page.
Someone asked about challenge level 5. Make a medium sized explosion in the exact middle, so the orbs all go to the corners and aren't too fast. Then, make a really big circle, so, when all of the orbs come back to the middle you'll be able to explode them all in one go.
I agree with some previous comments, repicking my starter cards would be nice..I kind of picked on looks and before I didn't know that much about the game.
 "Epic war"){kind=icon}
 "Achilles"){kind=icon}
 "Brute Wars"){kind=icon}
 "Cirplosion"){kind=icon}
 "Dog Eat Dog"){kind=icon}
 "Bubble Tanks 2"){kind=icon}
 "Kongai"){kind=icon}
 "Portal: The Flash Version"){kind=icon}
 "Pandemic 2"){kind=icon}