I'd say 250k is a success for most games, 500k for the bigger budget A games, 1 million for the AAA titles, especially those expensive PS3 games.
As for when they can be declared, that really depends on how the game sells. I'd say you really can't write off a game if it's moving 10k units per week or more. If that game can sell 10k units per week for a year, that's 500k units. So don't look at launch day or first week sales, declare the patient dead once sales stagnate.

"The worst part about these reviews is they are [subjective]--and their scores often depend on how drunk you got the media at a Street Fighter event." — Mona Hamilton, Capcom Senior VP of Marketing
*Image indefinitely borrowed from BrainBoxLtd without his consent.







