Ive played a game like this, and I decided to play until 2 powers were eliminated, then go by IPC’s to determine the winner.
First, Russia was eliminated. This took some time, as there was a good border alliance with Germany (really helped both players).
Next, Japan was bloackaded by a massive american fleet and they were taken out next.
Britain survived by ignoring trying to save IPC’s and instead defending their capital. They placed third.
Germany placed second, getting half of africa and the middle east, and the valuable european Russia territory.
The United States won. They controlled the other half of africa and dominated the pacific, and controlled the asian part of Russia.