Gamerlive.tv has reported that the game has hit the milestone just two months since launch.
Developer 4T2 Multimedia created the third-person, action adventure game, which is designed to look and feel like a AAA console title, yet be playable in a browser.
The game features a tailored control system which makes it easy for children from seven to 12 to navigate complex 3D obstacles, target enemies and experience rich gameplay.
Each of the toys in the new Hero Factory 2012 range contain a chest plate with a unique code stamped on it, which can be used to unlock game points, in the online game.
The game and the codes also form the basis of the 2012 advertising campaign for Hero Factory, making this into a project which covers TV, print, online and mobile.
Jan Faltum, marketing director, Lego Constraction, commented: "Joining the physical product to the range’s online world is a part of a broader strategy for Lego.
"Our toys are focused on creating a rich play experience for children and we see digital media as an increasingly important part of that. We commissioned this game so children could have fun customising their own heroes and interacting with them in a 3D world. The game codes connect the real world of their LEGO toys, with a digital world with its own creative possibilities."
John White, managing director at 4T2, added: "This is the biggest game we have produced to date. The potential visual quality of browser-based games has increased substantially in the last 12 months and player expectations have also evolved.
"Adrian’s production expertise, combined with Unity’s powerful features, have enabled us to create an action-packed game, with a storyline spanning many different 3D worlds, in a fraction of the time possible a couple of years ago."