Yes, well everybody outside Russia knows it didn't.
Scott Ritter explains the initial problems
here(He gets a bit carried away towards the end, mind)
If the Minsk agreement had been implemented by Ukraine, Donbas wouldn't have needed liberating.
How's that working for him?
He planned on the basis that the West wouldn't pour weapons in. So, not well. I mean, I would welcome a retreat by the entire Russian army, but I think this will be less likely now they have mobilised.
Not yet. I suspect, if Ukraine had been a success, those plans might have changed.
Zelensky wants you to think that. But the other countries are protected by NATO and are not AFAIK in border disputes with Russia.
Plus, Putin wants guarantees that US nuclear weapons will not be based in Ukraine , like they were in Italy and Turkey before the Cuban missile crisis. That's why he wants to prevent Ukraine joining NATO. I'm not sure, but I suspect it's also because he thinks the West wants Russia broken up and weakened, as he said in his latest address.