If derek dies, you need stardust to revive it, it doesnt matter what other activities you do it increase its health, its still considered dead. If you have derek dead and you cant afford the stardust, theres a reason why there is a slot machine
On the discord Crede has said that the PlanetLife.space version is going to be discontinued and not going to be updated. They have said about taking it down, but i guess its still there.