How do I unlock all the characters/stages in Super Smash Bros. 64?

What are the unlock conditions for all the characters & stages in the original Super Smash Bros. for Nintendo 64?

Jigglypuff

• Complete 1P Game (Classic Mode)

Captain Falcon

• Complete 1P Game (Classic Mode) in under 18 minutes

Luigi

• Complete Break the Targets with all 8 starting characters

Ness

• Complete 1P Game (Classic Mode) with 3 lives on normal or harder difficulty without using continues

Mushroom Kingdom (Stage)

• Complete 1P Game (Classic Mode) with all 8 original characters

Sound Test (Mode)

• Complete Break the Targets and Board the Platforms with all characters

Item Switch (Mode)

• Play 100 rounds of Multiplayer

Source: Smash Wiki

See also:

• How do you unlock all of the characters in SSB4?
• How do I unlock all of the stages in Smash Bros for Wii U?