This is lengthy, but here are all of the things that Wikipedia lists as pinball firsts:
First pinball machine that was commercially successful: Gottlieb's Baffle Ball (1931)
First pinball machine with a tilt mechanism: Williams' Advance (1932)
First pinball machine with a bumper: Bally's Bumper (1936)
First pinball machine with full-sized backglass: Dux (1937)
First pinball machine to use flippers: Humpty Dumpty (1947)
First pinball machine to use \"jet bumpers\" and locate the flippers at lower end of playfield: Williams' Saratoga (1948)
First pinball machine with score wheels: Williams' Army Navy (1953)
First pinball machine to use a ramp on playfield: Williams' Nine Sisters (1953)
First pinball machine for four players: Gottlieb's Super Jumbo (1954)
First pinball machine with multiball: Bally's Balls-a-Poppin' (1956)
First pinball machine to feature a single shot for one million points: Williams' Arrow Head (1957)
First pinball machine with a moving target: Williams' Magic Clock (1960)
First pinball machine to award an extra ball: Gottlieb's Flipper (1960)
First pinball machine to use drop targets: Williams' Vagabond (1962)
First pinball machine to feature an up post: Williams' Cabaret (1968)
First pinball machine to use a microprocessor: Mirco Games' Spirit of 76 (1975)
First pinball machine that spoke (a seven-word vocabulary): Williams' Gorgar (1979)
First pinball machine to use skee-balls (the largest commercial game ever built): Atari's Hercules (1979)
First pinball machine with multi-ball in the solid-state electronics era: Williams' Firepower (1980)
First pinball machine with \"lane advance\" (player control of top rollover lane lights): Williams' Firepower (1980)
First pinball machine with two-level playfield: Williams' Black Knight (1980)
First pinball machine with Magna-Save (player-controlled magnet to prevent outlane drains): Williams' Black Knight (1980)
First pinball machine with reverse playfield: Gottlieb's Black Hole (1981)
First pinball machine to combine mechanical pinball with a video game: Gottlieb's Caveman (1982)
First pinball machine with a three-level playfield: Gottlieb's Haunted House (1982) ↑
First pinball machine to feature a single shot for one million points in the solid-state electronics era: Williams' Comet (1985)
First pinball machine with an alpha-numeric display: Gottlieb's Chicago Cubs: Triple Play (1985)
First pinball machine to auto-adjust replay scores based on game history: Williams' High Speed (1986)
First pinball machine to feature a complete song/soundtrack: Williams' High Speed (1986)
First pinball machine with a jackpot that carried over between games: Williams' High Speed (1986)
First pinball machine to feature a wizard mode (high-scoring mode): Williams' Black Knight 2000 (1989)
First pinball machine to feature a known celebrity voice (Cassandra Peterson - Elvira) especially recorded for the machine: Bally's Elvira and the Party Monsters (1989)
First pinball machine with a dot matrix scoring display: Data East's Checkpoint (1991)
First pinball machine to feature a choice of alternate soundtracks (selected by the player): Data East's Checkpoint (1991)
First pinball machine without a plunger (a trigger-operated gun is used instead): Williams' Terminator 2: Judgment Day (1991)
First pinball machine with a cannon-launcher (player literally \"shoots\" captured pinball at targets): Williams' Terminator 2: Judgment Day (1991)
First pinball machine with a built-in dollar bill validator: Data East's Lethal Weapon 3 (1992)
First pinball machine to reward for a \"death save\": Data East's The Adventures of Rocky and Bullwinkle and Friends (1993)
First pinball machine to use a non-metallic, ceramic pinball (called a \"Powerball\"): Bally's Twilight Zone (1993)
First pinball machine with a player-controlled mini playfield: Williams' Indiana Jones: The Pinball Adventure (1993)
First pinball machine with multiple cannon-launchers: Williams' Star Trek: The Next Generation (1993)
First pinball machine to overlay interactive video onto the mechanical playfield: Williams' Revenge From Mars (1999)