[quote name='chimpmeister']your tiny list really is kind of pointless.[/QUOTE]
Done making a better list of UMD-only titles (this is only counting PSN and UMDs released in the US, there are probably a few more for other regions). I'd say there are PLENTY of games you can only play on a UMD-capable PSP:
2006 FIFA World Cup: Germany
2010 FIFA World Cup: South Afrika
50 Cent Bulletproof: G Unit Edition
Ace Combat X: Skies of Deception
After Burner: Black Falcon
Air Conflicts: Aces of World War II
Aliens vs. Predator: Requiem
Ape Escape: Academy
Atari Classics Evolved
ATV Offroad Fury Blazin Trails
ATV Offroad Fury Pro
Avatar: The Last Airbender
B-Boy
Battlezone
Beowulf: The Game
Bigs, The
Bigs 2, The
Bliss Island
Blitz Overtime
Blokus Portable: Steambot Championship
Blood Bowl
Bounty Hounds
Brave Story: New Traveler
Brooktown High: Senior Year
Bubble Bobble Evolution
Bust-a-Move Deluxe
Cabela's Legendary Adventures
Cake Mania: Baker's Challenge
Call Of Duty: Roads To Victory
Carol Vorderman's Sudoku
Cars
Cars: Race O Rama
Chessmaster: The Art of Learning
Chili Con Carnage
CID The Dummy
Code Lyoko: Quest for Infinity
Coded Arms: Contagion
Cube
Dave Mirra: BMX Challenge
Dead to Rights: Reckoning
Diner Dash
DJ Max Fever
Downstream Panic!
Dragon Ball: Evolution
Dragon Ball Z: Shin Budokai
Dragon Ball Z: Shin Budokai Another Road
Dragon Ball Z: Tenkaichi Tag Team
DT Carnage
Dungeon Maker II: The Hidden War
Dungeon Siege: Throne of Agony
Dungeons & Dragons Tactics
EA Replay
Eragon
Every Extend Extra
Exit
EyePet
F1 Formula 1 2009
Family Guy: Video Game
Fast and the Furious, The
FIFA Soccer (aka FIFA Soccer 05)
FIFA Soccer 06
FIFA Soccer 07
FIFA Soccer 08
FIFA Soccer 09
FIFA Soccer 10
FIFA Street 2
Final Fantasy
Final Fantasy II
Final Fantasy VII: Crisis Core
Flatout: Head On
Ford Bold Moves Street Racing
Ford Racing Off Road
Frantix
Frogger: Helmet Chaos
From Russia With Love: 007
Full Auto 2: Battlelines
G-Force
Generation of Chaos
Ghost in the Shell: Stand Alone Complex
Ghost Rider
Gitaroo Man Lives!
Go! Sudoku
Godfather, The: Mob Wars
Golden Compass, The
Gretzky NHL
Gretzky NHL 06
GripShift
Guilty Gear Judgment
Gunpey
Hammerin' Hero
Hannah Montana: Rock Out the Show
Hard Rock Casino
Harry Potter and the Goblet of Fire
Harry Potter and the Half Blood Prince
Harry Potter and the Order of the Phoenix
Harvey Birdman: Attorney at Law
Heatseeker
Hellboy: The Science Of Evil
Hot Pixel
Hot Wheels Ultimate Racing
Hustle, The: Detroit Streets
Infected
Invizimals
Invizimals 2: Shadow Zone
Iron Man
Iron Man 2
Jackass: The Video Game
Juiced: Eliminator
Juiced 2: Hot Import Nights
Kao Challengers
King Kong, Peter Jackson's: The Official Game of the Movie
Kingdom Hearts: Birth by Sleep
Legend of Heroes, The
Legend of Heroes II, The: Prophecy of the Moonlight Witch
Legend of Heroes III, The
Legend of the Dragon
LEGO Indiana Jones 2: The Adventure Continues
LEGO Star Wars II: The Original Trilogy
Lord of the Rings, The: Tactics
Lumines
Lumines II
M.A.C.H. Modified Air Combat Heroes
Madden NFL 06
Madden NFL 07
Madden NFL 08
Madden NFL 09
Madden NFL 10
Major League Baseball 2K6
Major League Baseball 2K7
Major League Baseball 2K8
Major League Baseball 2K9
Marvel Nemesis Rise of the Imperfects
Marvel Trading Card Game
Marvel Ultimate Alliance
Marvel Ultimate Alliance 2
Mega Man Powered Up
Megamind
Metal Gear Acid
Metal Gear Acid 2
Miami Vice: The Game
Micro Machines V4
Midnight Club 3: DUB Edition
MLB (aka. MLB 2005)
MLB 06: The Show
MLB 07: The Show
MLB 08: The Show
MLB 09: The Show
Monster Hunter Freedom
Monster Hunter Freedom 2
Monster Jam: Urban Assault
Monster Kingdom: Jewel Summoner
Moto GP
MTX Mototrax
MVP Baseball
MX vs. ATV: On The Edge
MX vs. ATV: Reflex
MX vs. ATV: Untamed
My Spanish Coach
Mytran Wars
N+
Namco Museum Battle Collection
Napoleon Dynamite
Naruto Shippuden: Kizuna Drive
Naruto Shippuden: Ultimate Ninja Heroes 3
Naruto Shippuden: Legends: Akatsuki Rising
Naruto: Ultimate Ninja Heroes
Naruto: Ultimate Ninja Heroes 2: The Phantom Fortress
NASCAR
NBA 06
NBA 07
NBA 08: Block Party
NBA 09: The Inside
NBA 10: The Inside
NBA Ballers Rebound
NBA Live 06
NBA Live 07
NBA Live 08
NBA Live 09
NBA Live 10
NBA Street Showdown
NCAA Football 07
NCAA Football 09
Need for Speed: Most Wanted 5-1-0
Need for Speed: Undercover
NeverLand Card Battles
NFL Street 2: Unleashed
NFL Street 3
NHL 07
NHRA Drag Racing: Countdown to the Championship
Obscure: The Aftermath
Online Chess Kingdoms
Open Season
Outrun 2006: Coast to Coast
Over the Hedge: Hammy Goes Nuts
Pac-Man World 3
Pac-Man World Rally
Pangya: Fantasy Golf
Payout: Poker & Casino
PDC World Championship Darts
PES 2008: Pro Evolution Soccer
PES 2009: Pro Evolution Soccer
PES 2010: Pro Evolution Soccer
PES 2011: Pro Evolution Soccer
PES 2012: Pro Evolution Soccer
PES 2013: Pro Evolution Soccer
Phantasy Star Portable
Phantasy Star Portable 2
Pimp My Ride
Pinball Hall of Fame: The Williams Collection
Pipe Mania
Pirates, Sid Meier's
Pirates of the Caribbean: At World's End
Pirates of the Caribbean Dead Man's Chest
Platypus
Pocket Racers
Popolocrois
PQ: Practical Intelligence Quotient
PQ2: Practical Intelligence Quotient 2
Pro Stroke Golf: World Tour 2007
Puzzle Guzzle
Puzzle Scape
R-Type Command
Race Driver 2006
Rainbow Island: Evolution
Ratatouille
Ratchet & Clank: Size Matters
Rocky Balboa
RUSH
SBK Superbike World Championship (aka. SBK 2008)
Scarface: Money. Power. Respect.
Scooby-Doo! Who's Watching Who?
Sega Rally Revo
Shadow of Destiny
Shaun White Snowboarding
Shepherd's Crossing
Shrek The Third
Shrek Smash & Crash Racing
Simpsons Game, The
Smart Bomb
Smash Court Tennis 3
Snoopy Vs. The Red Baron
Space Invaders Extreme
Spectral Souls: Resurrection of the Ethereal Empire
Spelling Challenges and More
Spider-Man 2
Spider-Man 3
Spider-Man: Friend or Foe
Spider-Man: Web of Shadows
SpongeBob Squarepants The Yellow Avenger
SpongeBob's Truth or Square
SSX On Tour
Stacked with Daniel Negreanu
Star Ocean: The First Departure
Star Ocean: The Second Evolution
Star Trek: Tactical Assault
Star Wars: Lethal Alliance
Steambot Chronicles: Battle Tournament
Steel Horizon
Street Supremacy
Surf's Up
Syphon Filter: Dark mirror
Syphon Filter: Logan's Shadow
Taito Legends Power Up
Tales Of The World: Radiant Mythology
Tekken: Dark Resurrection
Tenchu: Shadow Assassins
Test Drive Unlimited
Thrillville
Tiger Woods PGA Tour
Tiger Woods PGA Tour 06
Tiger Woods PGA Tour 07
Tiger Woods PGA Tour 08
Tiger Woods PGA Tour 09
TMNT
Tony Hawk's Project 8
Tony Hawk's Underground 2 Remix
Toy Story 3
Transformers: The Game
Transformers: Revenge of the Fallen
Traxxpad: Portable Studio
UEFA Champions League 2006-2007
UEFA Euro 2008
Ultimate Block Party
UP
Valkyrie Profile: Lenneth
Viewtiful Joe Red Hot Rumble
Virtua Tennis World Tour
Virtua Tennis 3
Wall-E
Warhammer 40k: Squad Command
Warhammer WarCry: Battle for Atluma
Winning Eleven: Pro Evolution Soccer 2007
Winx Club: Join The Club
World Championship Cards
World Championship Poker: All In
World Championship Poker 2 with Howard Lederer
World Poker Tour
World Series of Poker, The Official Game: Play the Pros
World Series of Poker: Tournament of Champions : 2007 Edition
World Series of Poker 2008: Battle for the Bracelets
World Soccer Winning Eleven 9
World Tour Soccer
World Tour Soccer 06
Worms: Open Warfare
Worms: Open Warfare 2
WRC: FIA World Rally Championship
WWE Smackdown vs Raw 2006
WWE Smackdown vs Raw 2007
WWE Smackdown vs Raw 2008
X-men Legends II: Rise of Apocalypse
X-Men Origins: Wolverine
Xiaolin Showdown
Yu-Gi-Oh! 5D's Tag Force
Yu-Gi-Oh! 5D's Tag Force 2
Yu-Gi-Oh! 5D's Tag Force 4
Yu-Gi-Oh! 5D's Tag Force 5
Ys The Ark of Napishtim