When entering The Tower of Sisyphus, you get to keep all your permanent upgrades, like the Atropian Blade and hookshot, but you lose all non-permanent items, like guns, artifacts and parasites.
When entering The Tower of Sisyphus, you get to keep all your permanent upgrades, like the Atropian Blade and hookshot, but you lose all non-permanent items, like guns, artifacts and parasites.