Differences (from memory):
Second Edition adds/changes:
-Destroyers
-Cruisers
-Two hit battleships
-AAA (now a combat unit and nation specific)
-Strategic bomb damage works differently
-New costs for most units
-New rules for subs and destroyers
-Completely revised map: Lots more territories and sea zones; income levels and starting unit counts are very different (favors axis); the Atlantic ocean now takes two turns to cross for East USA to England; fighters have to land in Iceland or carrier otherwise don’t have enough range; China and the Pacific Ocean are much revised, et al