You’re confusing yourself because you’re mixing scoring systems—first you say that the game is zero sum, win or lose, then you talk about variable sum game resources. In a zero sum game, the total score is always the same; you can either steal points or give them away, but can never destroy them. If the total score changes throughout the game, then you’re not talking about a zero sum game. There’s no different levels, though you can play a zero sum game as a variable sum game (I won while at full health!).
You’re confusing yourself because you’re mixing scoring systems—first you say that the game is zero sum, win or lose, then you talk about variable sum game resources. In a zero sum game, the total score is always the same; you can either steal points or give them away, but can never destroy them. If the total score changes throughout the game, then you’re not talking about a zero sum game. There’s no different levels, though you can play a zero sum game as a variable sum game (I won while at full health!).