Ruination

This achievement is earned by completely ruining 25 floors. Progress for this achievement is recorded every time you take make a floor go from nearly ruined to completely ruined (the last ruin level). No progress is given for ruining until that last ruin level. Because this doesn't work quite as you might expect, it's possible to ruin a floor only once, taking it from nearly to completely ruined and earning 1 progress towards the achievement. Thus, it is in a Strong Zombie's best interest to find floors that are already partially ruined to earn this achievement.