As anybody who drinks alcohol will know, it's not uncommon for memories to emerge from the fog of a particularly reckless drinking session, sometimes days or weeks after the event.
These memories tend to be pretty unacceptable, but playing Symmetrain at the Pocket Gamer party in Cologne last week is a happy exception.
Symmetrain is a quietly picturesque combination of auto-runner and spot-the-difference puzzle. A train travels upwards through the vertically scrolling stages, and on either side of the track are various objects – trees, people, buildings, boats, etc.
The two sides of the track are almost mirror images of each other, and your sole task in the game is to identify missing objects and prod the screen where they're supposed to be, at which point they magically appear, restoring the background to full symmetry. Whenever you fail to do this, you lose a bit of speed and sink towards the bottom of the screen.
I choo-choo choose you
As you play you'll be able to unlock faster trains, and an emergency brake will let you stop the train for a moment to compose yourself and spot all the differences in your immediate environment.
It's an ingenious concept, and it works well in practice. The controls are simple and responsive, and the whole thing is lifted by some excellent, picturebook-style hand-drawn artwork.
I had my reservations, chief among them being that Symmetrain just isn't very challenging. After playing without particular fear of failure for a couple of minutes I started again at the toughest difficulty and found I was still able to progress fairly easily – though I only played with one train, and it must be said that I did eventually succumb to panic and ineptitude.
The basic premise of Symmetrain is innovative and the game looks beautiful. If it can acquire a bit more challenge and variety before it finally arrives on the App Store later this year it'll be well worth a download.