This really should be National Tactical Advantages that comes from hundred years of military traditions. But when I read through the threads here, the majority of Advantages seems to be weapons developments, terrain and weather. USA were not the only nation with Paratroops, and Russia were not the only with Trains. So here comes my favorite list.
Do mind that the cost, movement and combat value of the units stay the same, as OOB. A Tactical Advantage is how the military leaders of that nation used the units.
1. PanzerShock. Each German Tank absorb, or negate one hit, this means it takes two hits to kill a German Tank.
The reason is German Panzerdivisions attacked as shockwaves at the weak point at the enemy line, breakthrough it, cut the supply and made the enemy surrender. This way of attacking produced less casualties than the infantry and artillery meat grinder, so every Tank save German lives.
2. PanzerBlitz. German Tanks can double-move, both during combat and non-combat movement.
2a. German Tanks that were not used so far, can Blitz through newly captured territory, and undefended enemy territory, and resolve combat in the next territory.
2b. German Tanks that moved into an adjacent territory and resolved combat there, can retreat into any adjacent friendly territory during non-combat move.
This is the historical correct way that German Panzer divisons were used. No other nations would do the same. All other nations would use Tanks as slow infantry support weapons.
1. Scorched Earth.
1a. When you take a Russian territory, all facilities are destroyed and removed from map. Put a damage token to cover the IPC value, the conquer can not collect income from this territory before he have payed 1 IPC to remove the Damage-token in his next Phurchase and Repair phase.
This is Russian military tradition from hundreds of years back, and no other nations, not even Germany, did this on a large scale.
1b. Russian defending units that survived the first round of attack, can retreat to any adjacent friendly territory that is not under attack.
This too is a typical traditional Russian way of warfare, trade land for time.
2. Partisans. During Mobilize Units phase, Russia can place one single infantry on territories without factories. Even occupied Russian territories that are not protected by enemy units.
This happened all the time in Russia, but nowhere else.
…is now recognized as a great Sea Power with supreme sailors.
1. Defending UK ships can retreat from a seazone when enemy naval units combat move into it, and before combat is resolved. Enemy aircrafts abort this retreat.
The Brits did in fact decode the Enigma, were masters in espionage, and the worlds best sailors since Nelson
2. Defending UK Infantry can retreat into an adjacent seazone that have one or more Trannies. The trannies cargo limit is still in force.
The Brits did in fact evacuate infantry from shore to Trannies several times, Dunkirk, Greece, Crete etc
1. Kamikaze. Japan is the only player with an exclusive National Advantage rule in every edition of the A&A games.
…great economy and worlds largest Airforce
1. Lend and Lease. USA can give money to other nations like Russia and UK, or France if it survives long enough.
a. Place a Convoy unit (buy at HBG), at a seazone in the North Atlantic, and as long this is not sunk by Germany, USA can give a friend like 3 or 5 IPC for every Convoy that are afloat during that players collect income phase. This rule need to some more work.
b. Place a Resource Token (buy at HBG) on a US Tranny, and move it to a territory that belong to the receiver. If it makes it, the receiver turn the token into IPCs
2. Carpet Bombing.
During the SBR phase, US Heavy Bombers can do one round of Carpet bombing against land units.
1. Move Bombers, Tacs and escort fighters into the contested territory.
Defender commit intercepting fighters
2. One round of air-to-air dogfight.
All attacking planes roll 1 as a hit, defending fighters roll 2 or less as hit.
3. Surviving Bombers and Tacs choose to SBR factories, Ports or airfields. So far OOB. US Bombers can also choose to Carpet Bomb land units.
Facilities roll AA fire to the planes, and if it is an AA-gun unit present, it too fire against the Bombers that are Carpeting.
4. The bombers roll for facility damage OOB, and the carpet Bombers roll to kill land units. Every Carpet bomber roll 2 dice, each 2 or less is a hit, and the casualties are removed, and since this is preemptive fire, before the attacking land units have moved into the territory, the casualties can not return fire. But, like when Battleships do Shore Bombardment, every Bomber need a matching attacking land unit to do the Carpet bombing.
Only USA had large enough and many enough Heavy Bombers to do Carpet Bombing, so this is an exclusive USA National Advantage