Most weapons are unlocked by buying them or earning them in Shooting Galleries - However, there's a few extra ones for completing certain tasks.
Complete the indicated task to unlock the corresponding costume.
Successfully complete the game to unlock the following bonuses. Artwork Gallery, Extra Disaster Files, Final Shooting Gallery, Movie Gallery, Alternate Ending.
Get 50 titles or more(and for those who dont know what titles are you earn em as soon as the game is completed on any difficulty)