Boss Attack is a challenge mode available in the NICALiS ports of Cave Story. It is unlocked once players have completed Story Mode with the "best" ending. The goal of this challenge is to defeat all the bosses without dying in the order of which they are encountered in. Bosses that are optional to face in Story Mode are required in order to progress.
The entirety of Boss Attack takes place in a room that uses the same assets as the Core. At the start of the challenge, the player is equipped with the Polar Star and the 290 Counter is activated. The player then navigates Quote around the room and enters through doors to initiate boss fights. A statue of each boss near each door as well as the preamble text when the player interacts with a door indicates the boss that the player will face against. Boss battles retain the same patterns and phases as they do in Story Mode, but the battles take place in rooms that have a different aesthetic than their actual location in the main game.
If the player successfully defeats a boss, the screen fades back to the main hub, where they can proceed to the next boss fight. A room where a boss has already been defeated cannot be entered within the same playthrough.
Experience is found in capsules that are distributed throughout the hub area. Along with experience, Life Capsules can also be obtained in between most boss battles. Most weapons that are obtained can be found in chests, but the mandatory weapons, ie. the Fireball and Blade, are automatically equipped after defeating Igor and Rabid Toroko respectively. A weapon that requires trading in Story Mode can be acquired in Boss Attack by talking to Cthulhu in certain areas.
The player is given the option of getting Booster v0.8 before fighting the Core, thus allowing them to use the Booster during the Core battle and not allowing them to obtain the Tow Rope. Once the player defeats Iron Head, they are automatically equipped with Booster v2.0, which replaces the v0.8 if they were carrying it in their inventory. Thus, getting Booster v0.8 does not ultimately affect the player's ability to beat the challenge.
|Main||Cave Story • Curly Story|
|Challenges||Machine Gun Challenge • Boss Attack • Wind Fortress • Nemesis Challenge|