Difficulty

 offers four difficulty modes, with Easy being the easiest, and Lunatic being the toughest. Increasing the difficulty makes the enemies and bosses more aggressive, but the rewards will be greater in value. Four of the game's achievements require the player to beat the game on each of the game's difficulty levels, and there are a couple of other achievements that require beating the game on Lunatic under certain conditions.

Easy
"For newcomers. A starter mode recommended for beginners."

- In-game description

Easy is the newcomer difficulty mode available in the game. It is the easiest of all four difficulties, as the enemies fire small amounts of danmaku. As stated, it is recommended to players who are new to the manic shooter genre.

Normal
"For most players. A basic mode recommended for most players."

- In-game description

Normal is the difficulty mode where most players will see a challenge. While the mode is slightly more difficult than Easy, it is easier than Difficult or Lunatic. The enemies fire average amounts of danmaku but less than Difficult.

Difficult
"Arcade style. A challenge mode recommended for experienced players."

- In-game description

Difficult is a challenge mode meant to be for experienced players. As the name implies, it is harder than Easy and Normal but easier than Lunatic. The mode allows players to achieve many of the top high scores that can only be achieved by playing on Lunatic. The enemies fire slightly more danmaku than on Normal difficulty and the bosses are much more aggressive toward the player, though not as much on Lunatic.

Lunatic
"You will not survive. A mode not for the faint-hearted and will drive you nuts. Recommended for experts."

- In-game description

Lunatic is a mode intended for experts. It is the toughest difficulty level in the game. The most prominent feature is enemies firing substantially more danmaku. Upon selecting the mode, a warning is displayed, cautioning the player that some attacks will get pretty intense and will eventually cause lag, as the game has to handle each bullet in memory. Players with knowledge of the enemies' attacks, extreme caution, and heavy use of cover and patience is the key to beating stages on the difficulty. Players whose reflexes are not strong can easily get killed by the large amount of incoming danmaku.

Behind the Scenes

 * The in-game description for Lunatic is a reference to  ' s Veteran mode, which is also the hardest difficulty in the single-player campaign mode and displays the same text when the cursor is highlighted over it.