It's possibly because Escape games are often considered casual puzzle games rather than pure adventures. The main issue is that their stories often consist of "you're in a room, get out" with no explanation of why. An argument that can run and run.
Bars of Black and White
A story and a unique (in my experience) game mechanic involving messages hidden in bar codes (the bars of black and white)
A Bark in the Dark
No real story but I just remember enjoying it a lot.
The Trapped Trilogy
Trapped
Pursuit
Escape
A kidnapping and subsequent events. The story is a bit odd but it has voices which is fairly unusual in free games.
Being One
More "Escape the hideous space station lab". Waking in a tube can you find out who you really are?
You could of course just go to
this site given the name (probably variable quality though)
