It won't take forever to finish Valve's Portal, reckons level designer Kim Swift, who guided us through a playable demo of the game at last week's Game Developer Conference in San Francisco.
"Currently the game runs about four hours," she told us.
However, it seems it may take some getting used to, as one of our reporters was reduced to a gibbering wreck as he attempted to get to grips with it. Still, Swift was apologetic and reassuring about the difficulty curve, saying she'd rushed the tutorial to get us to the action.
"In the game we take you very step by step in terms of being able to use your portals," she added.
Portal is a single-player experience fit to tie your brain in knots. You'll use a portal gun to manipulate your environment and objects, and it looks set to have an impact comparable to Half-Life 2's gravity gun.
It's due for release with Half-Life 2: Episode 2 and Team Fortress 2 this winter on Xbox 360, PS3, and PC.
Pop over to our Episode 2 gamepage to see all the latest footage and screenshots of the game. Alternatively you can venture to the Portal teaser site for a taster of the gravity-defying puzzle-solving.