Zero Japanese air-plane costs 0 maintenance cost as opposed to 60 which is the base unit.

Great Lighthouse +1 counts for all units (Although not intended, I love this)

German unique trait does not add extra strength to either Zero fighters and Lightning American unique fighter

Combat crossing rivers is not defined well as units literally standing in a river sometimes do not count on the -3 damage from river

I imagine some of these are well known but wanted to point these out.

I think the search for this forum is terrible as it's hard to know what's already out there.

Love the game, hopefully new patches can look into these details