Half Life 2, the successor to one of the most popular first person shooter games in history, has finally hit the shops after five years of development.
But efforts to curb piracy have caused problems for gamers. Manufacturer Vivendi Universal Games requires shop-bought copies of the game to be authenticated online with partner Valve.
Such has been demand that servers were temporarily overwhelmed, but a message on the game's website claims that the problem has now been solved.
"We have resolved the issues that caused some to experience delays with Half-Life 2 authentication earlier today," the company said. "We appreciate your patience and hope everyone enjoys the game."
Half-Life 2 is also available as a direct download from Valve, and users who take this approach have recorded no problems.
The launch of the title was seriously delayed when hackers stole a large portion of the game's source code last year.
The original version of Half Life was used to build the game Counterstrike, which has become one of the most popular online games in history. A beta version of Counterstrike for Half-Life 2 is available here.
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