But Roblox is primarily a building game, not a market simulation. The game is physics-based and encourages both building things out of virtual blocks, and using scripting to code how items behave.

Roblox said that it has reached a milestone in user-generated games. It now has more than 1.7 million game creators on its Lego-like game platform.

The Lego Group is bringing three weeks of challenges, quests and exclusive rewards to Sega’s Sonic Speed Simulator in August.

Since its launch in 2006, the free-to-play, user-generated massively multiplayer online game Roblox has given millions of players the power to create hundreds of original games. Using building ...