Bear in mind if you hewed WW2 into an ideological conflict like this, China itself wasn't unified, as it was divided between the Nationalists and Communists. Assuming these divisions, there's no way the Chinese Nationalists side with the Soviet Union and the Chinese Communists, so really you have the Nationalist Chinese + Japan + US fighting the Communists Chinese + Soviet Union in the East.
We know how that war in miniature played out more or less, as those were more or less the sides of the conflicts in the Korean War in the 1950s. Oh, except that unlike the 1950s, the US wouldn't be fighting with the kid gloves on.
As such, you'd see very bloody and nasty fighting in China, but the combined weight of the US+Imperial Japan+Nationalist Chinese would likely see the Communist Chinese crushed there. The Soviet Union didn't have a good way to deploy troops into the region, the overland routes are harsh and not good for mass deployment, and using the trans-Siberian railroad puts the forces within range of the Pacific ocean, which the combined US+Japanese navy own completely. You'd see the western coast of the Soviet Union under Japanese and American occupation very quickly, what would bog them down more is pinning down and destroying the Chinese Communists, who were notable gurrilla fighters. However, with the US acting as a moral leash on the Japanese, you're not going to see events like the Rape of Nanking, thus the Chinese Nationalists would be much more amenable to working with them and the Chinese people wouldn't have as much sympathy towards the Communists as they did.
Long story short, the Pacific theater of the war is pretty much a lopsided "Imperialist" victory. Neither the Soviet Union nor Communist Chinese have the infrastructure or military power to be able to oppose the combined weight of the US+Japan, especially when they're siding with the Nationalist Chinese. Manpower, industry, and logistics all heavily favor the Pacific Imperialist powers, and you likely see some sort of division of the Pacific into allied sphere of influence with the Japanese claiming Korea and the western Soviet Union, while China keeps Taiwan and much of the South China Sea region under their influence. The US keeps the Philippines, obviously, and would insist on open seas for themselves, which in this scenario I think both Japan and China would willingly give.
That said, the European front is much, MUCH uglier. Without the Soviet/German front of WW2 that means both sides have a LOT more resources to throw at England and the Middle East. Given Soviet losses in the west, the Soviet Union is going to be desperate for warm water ports not under threat by the Imperial powers. England will be hard pressed to defend itself; however, if will be able to bring more of its navy into the Atlantic as unlike in the OTL WW2 it need not worry about protecting it's Pacific holdings, as the Pacific Imperial Powers have that covered and then some. This means that German submarine warfare is that much less effective, due to the higher concentration of British naval assets in the Atlantic (and also US naval assets as they don't need as much in the Pacific due to neither the Communist Chinese nor Soviet Union being major naval powers). This means that the British Isles are turned into a veritable fortress and any attempts to stage and invasion of them is going to be exceedingly difficult due to the sheer naval dominance of the combined British+US+Japanese navies give the Imperial side (seriously, those are the three most powerful navies of the period all on one side... they basically own the oceans and there's nothing the Continental Powers can really do to contest them).
This means you're going to see some spectacular air battles over the North Sea and English Channel. The critical point of contention that will see how well the Continental Powers can do is actually going to be... Spain.
You see, so long as the Imperial Powers hold Gibraltar they can freely move their fleets into the Mediterranean and keep supply lines open to North Africa and the Middle East. This is the major ground front of the war, as trying to fight on Continental Europe isn't feasible. For as much as the Imperial Powers own the seas, the land of Europe is the Continental Powers. They have the manpower and logistics to be able to contain and bottle up any landing the Imperial powers try and make in Europe.
North Africa, however, is a different matter. The land route supply lines to the Middle East and North Africa are crap even today, and in the 1940s even worse. As such, the Continental Powers would be hard pressed to keep supply lines open to them, they basically have to ship troops and supplies across the Med. However, as I noted, the sheer naval power disparity between the two groups means that such supply lines are risky and weak. However, unlike the oceans, the Med has a major choke point for entry from the Atlantic. This means that a major concern for the Continental Powers will be to seize Gibraltar in order to try and cut the Imperial powers from the Med. This means they need access to it... which means they need to go through Spain and Portugal to get there. The thing is, invading Spain from Europe isn't actually that easy, as there's a major mountain range right on the border between France and Spain. Further, the Imperials can get supplies to Spain via the Atlantic.
So you have bloody fighting in Spain, North Africa and in China/Siberia. It's anyone's game in Europe, and would greatly depend on the generals and events. Meanwhile, I don't see the Continental Powers doing well in East Asia. They just don't have the advantages necessary to pull it off, which means China rapidly is out of the Continental Power bloc and instead supporting the Imperial powers. This means that in the long term you have the Imperial Powers building up for a long march from the East into the heartland of the Soviet Union, while those powers are focused on trying to secure their African supply lines by securing the Med in a conflict mainly fought in Spain.