Garry Newman’s delightful sandbox physics game Garry’s Mod has hit an incredible milestone, selling 1 million copies since its inception as a simple Half-Life 2 modification six years ago.

Newman broke the news on his blog earlier today, thanking fans for their continued support. The game allows users to toy around with the robust physics engine in Valve’s Source SDK, which has led to the creation of many amusing videos – from spoofs to bloopers.

It’s an impressive feat, exemplified by the fact that only word of mouth drove sales for the most part. That, and Steam sales of course.

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