OK, played this for the first time last night, using a first draft copy of the rules, and it was interesting: briefly, the system worked overall with largely positive comments, but there was some constructive feedback about improvements that could be made.

A report on the content of the game can be found here http://wiki.mk-rpg.org.uk/index.php/The%20Memory%20Cheats but in brief, the players started in hospital beds, numb and unclear about anything at all, which is more or less the typical way for the game to begin.
As things progressed, it turned out that they were all beings from another plane of existence who had got stuck on Earth after a very bad, drunken idea of how to continue Yog-Sothoth's stag party; along the way, Azathoth kept looking for a cool beer and good music, whilst Lucifer drove the rest of the party around in his Taxi from Hell, while Jesus smacked H. P. Lovecraft (who was actually Lenin) for getting them all into this mess in the first place and, finally, the My Little Ponies inherited the Earth.

Points that arose:
1. Clear guidance at the start of the game.
While everyone enjoyed the story, they all agreed that it would be better if there was a clear setting at the start of the game, so that they had a better sense of bounds and the direction in which it would be acceptable to atke the narrative.

2. Guidance throughout the game.
At times, the players found their imagination flagging as they tried to think of intersting challenges, so it was suggested that the challenge-format be more clearly laid out and explained.

3. Simplify card management.
Many players ended up with a whole stack of face-down cards as a result of losing challenges and very little they could do with them, so it was suggested to either have another way of spending those cards, in addition to the options currenyl open, or  reduce the frequency with which more face-dwon cards were gained.

4. Give the GM more to do.
The GM in this game often only gets involved once or twice per act, so a move towards getting the GM to narrate more things, such as NPCs, was brought up.