Demos you admit made you buy the full game.

[Amarok]

Osmos (!)

World of Warcraft

Oddworld: Abe's Oddysee

 

[The_Healer]

Red Faction: Guerrilla

It was a fun game, but not as fun as the demo made out.

The demo for the first Sly game made me buy the entire series.

Your Avatar is disturbing! Make it stop, PLEASE!!!

 

[project23]

Company of Heroes - (public beta, preordered)
Warhammer Online - (public beta, preordered)
Eve Online - (trial account, converted to full account)
M.A.G. - (public beta, preordered but still not released)

Demo, Public Beta, Trial Account. Pretty much the same thing.

 

[Floppertje]

The force unleashed. A friend kept bashing it because of the story, which I admit sucks quite hard. But I really enjoyed the gameplay after playing the demo and I didn't regret it.

@RAND00M: your avatar is REALLY disturbing and distracting me from posting... I'm scaaared ...

 

[Sonny B]

Mirrors edge and baulders gate 2 (Possibly the longest demo ever)

 

[Biosophilogical]

The first Dark Cloud game. I had the demo and never got past the cat-bit, so I bought the full game.

 

[FROGGEman2]

Arkham, mainly.

 

[Mirroga]

Einhander. Best horizontal shooter ever!

 

[Nazulu]

I fell in love with the Starcraft demo. It might not seem so great now but it was a big improvement from Warcraft 2.

 

[Beartrucci]

UFC Undisputed 2009. Me and my older brother would play the demo non-stop, bought the game, played it all week and never touched it again.

yeah the thing i hate abotu that game is the carear mode, nobody ages and it FORCES you to retire in like 8 years, its stupid

I haven't even touched the Career mode, it didn't look that interesting. I really shouldn't of bought the game, it's lots of fun and good for when friends are over but I don't believe it was worth the money.

 

[Beatrix]

Ninja Blade!

And I loved it for all it was worth.

EDIT: And Tenchu Z, which was also a good choice.

 

[Korten12]

the only demo I remember was the dynasty warriors gundam demo made me buy the game.

 

[A Pious Cultist]

The psychonauts demo... fuck [i/]you[/i] Tim Schaffer and your misleading demos.

What do you mean?

 

[timmytom1]

For me, it would have to be Mirror's Edge, which was good until the last level.

Wwwwwait(yes that`s deliberate) you`re telling me you enjoyedthe jump between trains on the subway level?

 

[The Last Nomad]

-snip-

I wasnt actually planing on getting that game anymore... it was just an old dream of mine, guess I outgrew the idea of that game... but thanks for your concern

 

[willard3]

Peggle. Holy SHIT Peggle.

 

[Kiutu]

Not on impulse but Prey.