So is it possible to win as the allies after sea lion?
It is very much possible. This weekend I played against a friend, and decided to go for London/Calcutta. Both of us have like 20+ global games, so level of experience is past the newbie stadium ;)
I took both capitols round 4. However, Russia seeded massively into China, and actually liberated Calcutta later on - round 7ish. US went 80/20 pac/atl and harassed Japan big time, convoy raiding Tokyo, leading up to a huge naval battle outside of Hong Kong. Really smart blocking moves preventing return for Japanese navy to Tokyo… Utter failure for Japan (dices sooo not going my way), resulting in Japan loosing all ther naval forces after 2 more rounds.
The US then went 100% atlantic…
By that time I had Italy making about 50IPC, taken Africa, and middle east, pressing up to Caucasus, but loosing pace as a result of US pressure in the mediterranean.
Germany took London, with heavy casualties. Ended up with a huge battle in Eastern Poland where I routed USSR, but he kept his airforce, and managed to turtle Moscow, reinforced with Anzac fighters, and US mech/tanks from French Indochina.
Dice failed me twice on attacking Moscow, and from there it was downhill :p By far the biggest, most exciting game I ever had. Would like to see the outcome had Japan not been taken out the way it was. The game was wide open until Moscow. Odds were more or less 50-50, but then again, dice can never be trusted!!