Don't You Die On Me

Don't You Die On Me is an achievement/trophy in Dead Rising 2. It is unlocked by reviving your co-op partner in an online co-op game.

Guide
The easiest way to get the achievement is to kill your partner and revive them with food. Make sure your partner agrees to this though, as they may quit or kick you if you do it without warning. Alternatively you can just play co-op games til someone is killed, then revive them.