Garry's Mod has been released for Mac platform. It's $4.99 this week for PC or Mac, to celebrate. It's a Steamplay game, so buy for one platform, get both. I don't believe you can buy this anywhere but Steam anymore.
Excerpt from news release:
Excerpt from news release:
"What's Garry's Mod?," you might be asking yourself, dear Mac owner. It's the playground with which hilarious and spectacular videos like Half-Life: Full Life Consequences, 100 Ways To Kill Yourself in Garry's Mod and epic Rube Goldberg machines are created. It's not a game; it's a tool. And, like most new Steam releases, it's cheap. Just $4.99 USD.
Garry's Mod [Steam]