Really great concept. Reminds me of when you lose all your upgrades at the start of Castlevania: Symphony of the Night. I found myself not even using the shield during the first fight, so that was an easy sacrifice for round two. Zeus has a crazy amount of health, though. I think each successful attempt of mine lasted something like five minutes, which is a lot of time to be intensely focused for. I admittedly did not get past round two for that reason. I think Zeus should've gotten more health as you lose your upgrades, and maybe that's how much health he has at the very end; I wonder how good/different it would feel to be at the end and only have one upgrade! Very kind of you to let the player restart from the current level instead of the beginning of the game.