I'm not sure if it's really multiplayer. I tested to press start as soon as possible and i was never at the goal first. Even if i had o towers while everyone else had frost ones. Speed was also on3x and idk setting speed makes no sense in a real multiplayer.
Online multiplayer unlocks after completing stage 3 and is asynchronous: you compete against recorded runs from other players, with bots filling empty slots when needed.
Each match runs locally, so the speed setting affects everyone in that match. Pressing start begins the round for all sides together, so starting sooner doesn’t give you a head start over other players