If one uses the Level Select code in Viggo's Revenge, Tweek will be selected to battle Claude. Since he is already placed high enough, Tweek can enter and attack Claude. Throughout the process, Tweek will speak with Juliette's voice. However, since Tweek cannot climb, he is unable to complete the level.
In the Dreamcast version, if you exit the game after the game saves after defeating Claude, sometimes Bristol will not show up when you reload the file, but the game will acknowledge that you defeated Claude. However, due to Bristol not showing up, you will never get the Bullwhip and never complete the game.