It's possible to finish a game?
Never seems to happen with mine, I'll be on fire for a week or three and then something comes along and either makes it physically impossible to find time to write or else knocks me out of the zone some other way, and then it's a coinflip whether I'll be able to pick up where I started and continue on or now.
It just happened right now, for instance. Yesterday I was doing great and tonight I'm just too f***ing upset to write a single paragraph. :( I already know I won't have any time to myself this weekend, so that's out, but we'll see how things go tomorrow.