Full list of all 12 Plants vs. Zombies achievements worth 200 gamerscore. It takes around 15-20 hours to unlock all of the achievements on Xbox 360.
Completed adventure mode
Turned away the zombies even though all 5 lawnmowers were used
Bought at least $25,000 worth of stuff from Crazy Dave's trunk
A fallen Gargantuar makes for good fertilizer
Bowled a winner with a friend in Co-Op Wall-Nut Bowling
Planted your first 10 peashooters
Went on a crazy 5 game winning streak in VS mode
Collect all 49 plants in the game
Grow the Tree of Wisdom to at least 100 feet
Survive 40 waves of pure zombie ferocity
Blast 10 zombies at once with a Cherry Bomb!
Stop the horde using only the Sunflower, Wallnut, and Chomper on any level