Myst for the PSP is just £9.99 delivered from Play.com. Cheapest elsewhere is £16 from Amazon.
Details: Myst is an immersive experience that draws you in and won't let you go. You enter a unique setting, venturing alone to varied times and places, the worlds that compose Myst. There are no instructions, and you encounter no living beings but soon realize your actions may help individuals who are somehow trapped in a parallel dimension. The Myst adventure is like no other, tantalizing with its unique combination of lavish environments, puzzles, mazes, and a sizzling underlying drama which steadily unfolds to reward the player further still.