Too many of those borders are analogous to OTL. I'd suggest changing some, especially in Africa.
Aside from that, how did mega-Russia come about?
It shall be done.
A more decisive Ottoman-Russian War in 1813 led to the Russian empire "Freeing" Moldavia and Wallachia and incorporating them into the Russian Empire as Grand Duchies. Having another long land border with Russia especially with Austria now looking more to the West led to several other Russo-Ottoman Wars and the acquisition of Bulgaria and vassalization of Greece. Russian Sweden and Finland arose thanks to Sweden getting Pwned even harder than OTL in the French Wars of the late 18th century and early 19th. Russian Ezo comes from Russia opening Japan and there being no Meiji Restoration. Russia loped off chunks of China during the Sino-Russian War of 1878. In OTL General Zuo Zongtang was outspoken in calling for war against Russia, hoping to settle the matter by attacking Russian forces in Xinjiang with his Xiang army. ITTL The Russians are in a better position than in OTL and when the Chinese attack the Russians many Russian soldiers are killed holding their position. This resulted in a war that saw China get its ass kicked.
I'd also change the acquisition of island groups in the Pacific.
I'm on it.
S. America and Australia bother me...
Portuguese Africa needs some subdivisions. Like French East Africa though!
What's up with Greece?
May I ask why you dislike S. America and Australia?
Portuguese subdivisions shall be created. I'm glad you like French East Africa, I've always had a special place in my heart for it.
Greece is a vassal of the lovely Russian Empire.
Whatever happened to Sweden and Corea, I like it.
Sweden is explained in one of the above sections. As for Corea, it managed to pull a Meiji after the Sino-Russian War (not exactly sure how,yet, but even though I love the Russian Empire I didn't like the idea of it curb stomping all three of the North East Asian nations.
Russian Sweden? Russian Ezo?
Explained in the one of the above sections.