No, it's more like "move left" and you move left at your velocity (95, let's say) for that one frame. Next frame you can send any move, but it will only move yo

No, it's more like "move left" and you move left at your velocity (95, let's say) for that one frame. Next frame you can send any move, but it will only move you 95 spaces in that direction, no more. It's the same as just holding down a button on your keyboard - the game engine moves you according to the rules. Now you're just transmitting the fact that the player is facing NW and sent a move left command. You're just running the game on the server like you would on the user's machine. Conceptually it's actually simpler - you're just running the same thing on the server and sometimes backtrack in the client when the connection is laggy.