How do you erase certain parts of the memory?

[Kedjane]

This might be possible, but I highly doubt that it's going to be efficient in any way. You simply can't remove all traces of a memory. For this to work, I assume the patient need to be under a hypnosic state during the process? I mean, he needs to be hypnotized _while_ playing the game?

Although I have no doubts that you can lure and/or remove parts of your memory, there are certain parts that simply can't be removed, things controlled by instinct, like walking. I've heard about people with amnesia, they usually forget the name of people but not(for instance) what a fork is and how to use it. Is there some kind of mystery behind this?

Actually I've read a bit about memories and such and it's a bit obvious you haven't, at least not a lot.
I'm not expert or anything but memories aren't just that, there are "long time memories" and "short time memories". Long time memory is things like what your name is, where you live and how to write and short time memories are things like what was the last key you pressed or the last meal you had.
Only if something is considered "important to remember" by the brains automatic process (which you can't fully controll, which is why you can't remember some things even if you try really hard) it is moved from the short time memory to long time memory.

I think memories are "processed" and sorted into the brains "remember"/"forget" folders about six hours after something happening. This I read is why you for example after a traumatical can forget it if you play Tetris for roughly one hour about six hours after the event.
I don't know when non-traumatical events are processed, but there might be a rough estimate of that time too and could theoretically be used for removing good memories aswell, though a short time after playing the game.

This is more of an answer to that last part about amensia actually, but I think people with amnesia forget both their short time and long time memories, but they still have the bodys instict memories such as how to eat (and do fancy ninja moves, if you're Jason Bourne) but you can't remember things not a part of all people such as individual names and such.

Anyhow: if you can prevent memories from storing in the first place I don't doubt you can by lots of hypnotisation be made to forget something. Afterall if someone showed me a picture of the very first room in the Penumbra Tech Demo, but with red boxes instead of green, not having played the Tech Demo in a while just that might be enough to alter my memory and make me remember them as green.

But I've got to go so I can't elaborate any more right now.