HoshiChiri

I've never had a tamagotchi. Can't you reset them, perhaps remove and reinsert the battery or is it really one time? It must mean it writes to some non-volatile RAM (*) that it is game over.

Too bad about the loss though, and that the sale is over so you can't easily replace it.

(*) Or I suppose it could trigger some overvoltage or short circuit that burns out the circuits, effectively self-destructing the electronics but that sounds more like something that belongs in a spy movie than a kids' toy.

The internet says you can reset them. The "pen" hole on the back.

It probably depends on the actual unit, but it would seem most can be reset. Of course from a philosophical point of view, your first pet remains dead, though from a technological point of view, you would be able to replay it.