My wife started playing Plants vs Zombies on my account. Now I'd like her to have it on her own account (so that her steam sesion wouldn't interfere with mine). I've found that question: Can I transfer a Portal 2 saved game across accounts and platforms? but... does it actually work? Have someone tested it? I don't want to force her to play again from the very beginning. And to "lose" a copy of the game if it's not possible.
The game should recognize any saves that are in the appropriate folder. It worked on my Arkham Asylum ( back before steam did cloud saves ), and worked with Portal 2.
Unfortunately, I cannot confirm for that specific game without purchasing two copies of that game.
It's definitely possible with Plants vs Zombies. I had to copy saves between accounts in steam folder (saves stored in windows user settings folder appear to be some sort of cache and copying them doesn't work), and it did the trick.
Depends on the game. There are games (like Call of Duty: Modern Warfare) where the savegames are encrypted using the CD key of the users, so you can't transfer them to another player.