MTG Salvation

if i had platinum angel on field and a opponent attacking say with 40 damage and anouther blocks it. i cast arcbond on defending creature we all get hit with 40 damage and all creatures as well do i lose the game at same time my opponents do or do i win the game if we all drop to 0 hp?.
Moved to Rulings (and added card tags because I am a benevolent deity) -KnickM

It seems the answer is a bit complicated, so I will let someone else answer it.

I'm just adding card tags:

Arcbond
Platinum Angel

You win that game. During the first check of SBAs right after the Arcbond trigger resolved, all players will lose the game simultaneously with all creatures being destroyded for having lethal damage marked. Alas, you can't lose the game yet, because the Angel is still there. A second check right afterwards would make you lose the game, but hey, you are the only player left in the game, so that second check never happens because you won. Unlike losing the game, winning the game happens immediately.

104.2a A player still in the game wins the game if that player’s opponents have all left the game. This happens immediately and overrides all effects that would preclude that player from winning the game.