The launch of Grand Theft Auto Online has hit substantial teething problems, as the anticipated flood of players has stretched Rockstar Games's servers to breaking point.
Players have faced multiple error messages such as: "Rockstar cloud servers unavailable," as well as screen freezing and slow loading problems.
One message says: "Mission failed," as soon as a mission begins.
Rockstar said it was "working round the clock" to resolve the issues.
"We apologise for any inconvenience and thank you for your patience while we work to resolve this," the company said on its website.
Console makers, such as Sony PlayStation, have been fielding complaints from frustrated players experiencing problems with the game.
Meanwhile angry players have been making their feelings known on Twitter. One wrote: "GTA online has more launch problems than North Korea..."
Last week Rockstar North admitted it was facing "unanticipated" pressure because sales of GTA 5 had been stronger than expected.
"We are working around the clock to buy and add more servers," its blog said.
But it added that matters could be "more temperamental than such things usually are" because using so many computers introduced their own issues.
In the online version of the 18-rated violent crime game, up to 16 players can interact simultaneously within a virtual environment and create personalised avatars.
It is included free with every copy of the GTA 5 console video game. According to one analyst's figures, more than 15 million units of the title had been sold by early last week.
"At a conservative estimate I would expect about two million players to log on to GTA Online within the first 24 hours," added Keza MacDonald, UK games editor for IGN.com, the video game and entertainment site.
"Rockstar has never done an online game of this scale before, so they are totally unproven in terms of their network infrastructure.
"And even the highly successful World of Warcraft at its peak didn't have as many people playing online at once as GTA is likely to have, so it wouldn't surprise me if there were problems."
Other bestsellers have faced issues after their servers failed to cope with demand.
Owners of Electronic Art's Sim City - which requires players to be logged into its servers to play - experienced waits of up to 30 minutes to get started and then sluggish gameplay when it went on sale in March.
EA later apologised and offered a free title to those affected as compensation. It said more people had logged on than it had expected, adding they then played differently to the way its testers had.
The previous year Activision Blizzard saw its servers for Diablo 3 come under severe pressure after its launch.
The term #error37 trended on Twitter after players were shown the code alongside a message telling them to wait and try logging on later. At one point the firm took its websites offline to reduce demand.