When people talk about WW2 they often talk about how, at the beginning, US had the 14th to 16th largest military in the world, while, at the end, US had produced more war material than the rest of the world combined. What people often miss is there were critical points in the war where things could have swung the outcome of the war in other ways in the 2.5 years it took USA to land troops in France.
Most people know that the German decision to attack Stalingrad instead of laying siege to it like Leningrad was a disastrous decision. Germany lost just one military casualty for every 6 military casualties the USSR suffered during the Leningrad siege. This is one reason why it lasted so long. This is also despite the fact the north was able to be supplied by Allied convoys. As there were no Allied convoys to Stalingrad, simply laying siege to it (even with a higher loss ratio of 1 to 3 or 4), as many German staff wanted, might have been enough to win the war, instead of attacking it and losing an entire army for nothing.
The main critical point in WW2 that many miss is that, at a certain time around mid 1942, USSR only had about 1000 armored vehicles and a few thousand planes left with which to fight Germany. This fact alone is not significant. But couple it with the fact that, at that very same point, USSR had received about 5000 armored vehicles and many thousands of planes from UK and USA, and a clear picture emerges. So, at this point and probably weeks to months earlier, USSR would have been out of WW2 because they would not have any heavy weapons to fight with. All the territory they gained or held with lend lease weapons would have gone to Germany with low losses. If US/UK had not done lend lease or had done it at a lower level, USSR was out.
There are literally dozens of close critical moments that could have swung the war one way or the other if things had been slightly different. A few are the almost complete lack of military production by Germany’s European allies, the decision of Finland to not help Germany take Leningrad when the opportunity was there early, the battle of Midway which should never have happened, the German tendency to split their attack power among smaller armies in 1942 and beyond instead of concentrating their force against USSR for an almost guaranteed big win, etc… This game simulates the fact that WW2 wasn’t over as soon as USA joined since it took 2.5 years for USA to build up and land troops in France.