I think that is one the main questions. What was my strategy with USSR ?
At the 1st turn i started to research level 1 in infantry weapons. Then, turns after turns, I researched, by prioryties, AA techs, infantry warfare (the bonus is free on the map, you don't need to upgrade your units with MPPs). Same with armored warfare (in order to have the 2 hits per turn) and aerial warfare.
I researched too advanced tanks and advanced fighters. Next command & control, spying (1point) and industrial technologies (1points) this from 1939 to 1942.
of course when i had level 1 infantry weapons i started immediatly to search level 2.
Drop fighters (and aerial warfare), you will never achieve tech parity or number superiority to make this work. Don't go for S&I too, USSR doesn't have luxury to pick macro techs. You already have 250 MPP to spend elsewhere, not counting MPP's to repair fighters.
IW2 in the middle of 1942 is very late. I usually get it in Autumn 1941, Feb 1942 is my latest, with atrocious low rolls. Did you get IW1 at first turn?
As mentioned, 2nd engie is very helpful.
It's hard to tell what failed in Spring 1942, perhaps unit placement and tactical play were little bit off. Smolensk fell in 1942 or already in 1941? Where did GER finish 1941?
Regarding convoys, it's better to box him in beforehand in North Sea, than to deal with naval warfare in northern part of map. Still, it should be doable. You have plenty of destroyers and 5 carriers. With ASW upgrade, other ships can join the fight. You will take losses, but he will too. And as mentioned, his bombers can't be everywhere. How many did he have there (in NOR)? What is more, without HQ supply there is very bad (5 and less).
But probably the most important thing about Russia, which wasn't mentioned at all. USSR doesn't fight in isolation. There are other Allied powers, except China, which will die. Harass him elsewhere, especially with UK. Bomb his mines. Land, take empty cities, he can't cover everything. As USA joins, MPP and time works in your favour, just kick him in different places, force to react and divert MPP's. Survive 1942 as Ivan, then land in force in 1943.
And what about China ? When japanese bombers started to hit supply sources, Chungkind and Kunming, the south chinese army was no longer supplied, and became fragile as glass. AA guns (units and cities) and fighters were usless. Again strategy impossible to counter ?
China is doomed (Devs don't like Nationalists [;)]) and you can't save them, you may only delay. Sometimes you may delay long enough to deterr Japan from attacking India/Russia. That's already huge.
About Hawai, i have to say that if Japan need to garnison the island next, it is a very small price to cut the route of the Pacific to the whole US navy. In order to advance the US Navy needs harbor level 10. Hawai, west coast except, has the only ones. and 4... It's a desaster for USA.
Not a disaster, just a setback. You have an excuse to take your fleet to Atlantic. In this game USA is not strong enough to fight both JAP and GER at full potential. Focus on one of them, preferably GER.
It seems in this game you faced a well-executed plan and didn't know how to react. Next time you will know and it will be a completely different story for Axis.