Splatoon Raiders' post-game content transforms the 15-hour campaign into a substantially deeper endgame experience. After beating the final boss, players unlock Super Spicy difficulty with mission levels reaching 80, followed by the Bottomless Buffet, an endless arena series that escalates to level 92 in challenge. This late-game content demands both mechanical skill and endurance, pitting players against waves of enemies that surround them from all sides, requiring constant movement and shooting to survive.

The core driver of post-game engagement is the deep customization system rather than difficulty alone. Every gadget can be extensively modified with perks that fundamentally change its functionality—a basic turret can become a two-unit spawner with explosive shots, increased range and fire rate, and additional effects like ink sprinklers. Combined with an overleveling system allowing progression beyond the level-50 cap, the endgame loop focuses on iterating and optimising builds, with well-configured loadouts eventually enabling largely passive gameplay strategies reminiscent of Vampire Survivors.