[downer86]

Well, in addition to nuclear being an area-of-effect spell, not unlike Cone of Cold, nuclear gets +10 to hit on range attacks like magic missile, and a percentile roll for critical damage.

The percentile table is:

  0-9%   - Immediate radiation sickness dealing additional 15HP of damage, and a lifetime of random, scattered benign tumors & cysts
  10-49% - Coin flip for damaged infertile gonads or ruined thyroid, damaged thyroid inflicts 5HP per day
  50-59% - Blindness
  60-69% - Leukemia, with a coin flip for six month or decade-long survivability
  70-79% - Other chronic malignant cancers with three year suvivability
  80-89% - Other acute malignant cancers with six month survivability
  90-99% - Instant death