What was the situation like for losses of major ships on both sides? Did the Japanese overwhelm or not? Did the AI bring lots of oil or fuel to Honshu are a human player must to keep industry running?
In the two Computer-Versus-Computer runs that have finished so far Japanese major warship losses were well below historical levels, Allied major warship losses were above historical. Major warship losses were similar in both Normal and Very Hard difficulty games.
After securing their defensive perimeter Japan goes on the defense, their CV's are usually only found in TF's with 4 CV's and a BB or two. The USN, always short of carriers, deploys their CV's in 1's and 2's. The slow pace of Allied counter-offensives into the Central and South-West Pacific don't help, as Japanese land based air seems to carry the bulk of the defensive burden. In both games ten USN BB's were sunk after 1941, all by air-dropped torpedoes. Can't tell what planes dropped them, but the exchanges didn't cost the Japanese any major warships (nothing lost in the area at the time). My impression is the USN computer player does not do a good job providing CAP over its forces.
In normal difficulty mode the Japanese efficiently advanced to their intended defensive line, taking over the Phillipines, Burma, the Netherlands East Indies, New Guinea, and the Solomons, pretty much on the historical timeline.
In Very Hard difficulty mode the Japanese again advanced to their intended defense line almost everywhere, but a bit slower. Except against the Dutch around Batavia. The Dutch Army was able to hang onto the western one-third of Java and held it for the entire war. It seems Very Hard helps ground defense more than offense, but not enough to help the Brits keep Burma.
Major warship losses in both games were about the same, for both sides. Losses for AK/AKL's were much higher in V.Hard mode, 80% higher for the Japanese, 20% higher for the Allies.
The description of Very Hard mode says – "Computer is given some logistical and combat advantages." The combat advantage showed up helping the Dutch Army, and in higher losses for both sides in air and ground forces. The logistical advantages really show up in the economic game. I looked at the Industry window for each save,
selecting "Bases at minimal requirements".
In Normal mode the Allies usually had 5-10 bases with a value in the red the whole war, the Japanese started with 0 at the beginning but by 1943 and through the rest of the war usually had 15-20+ bases in the red. Lots of oil and fuel shortages.
In Very Hard mode neither side ever had more than 1 or 2 bases in the red, mostly they had 0. Not sure if all that oil and fuel is actually being delivered or if the computer just gives itself however many are needed at each base each turn. That would be a logical way to give the a Computer Player a helping hand, and
probably the easiest. The few bases in the Red in Very Hard mode were mostly being actively fought over or had just been captured.
I don't believe that a Computer Versus Computer game will ever resemble the results of a Human vs Computer or Human vs Human game.
I would support the idea, that I have seen made in this forum, that if you are playing against the computer always play against a Very Hard difficulty opponent.