Old School

Old School is an achievement in Plants vs. Zombies Adventures. To achieve it, the player must beat a level without reviving any plants.

Strategy
The best way to earn it is to replay Level 1. Here, you must keep your plants from being stunned by the zombies. The best plant to use is an Aspearagus, because it can kill regular zombies in three hits. Freeze the last zombie before it gets to your Aspearagus before winning.