If the hardware doesn't have a clock that keeps track of the current time, the game could still re-seed based on the timing of player actions, because there's a

If the hardware doesn't have a clock that keeps track of the current time, the game could still re-seed based on the timing of player actions, because there's a certain amount of unpredictability there (at least, more than "seed with 0, only iterate on easily-controlled player actions"). It could do something like iterate the RNG every frame that the player doesn't move.