Starting on April 4, gamers can download the "Halo: Spartan Assault" through Steam.

But this top-down shooter game is not a new game though, as it was first released in 2013 for the PC, Windows Phone 8, Xbox One and Xbox 360, according to Cinemablend.

The site speculated that the reason why Microsoft is releasing one of its top games on Steam is probably because the company is testing how it will be perceived by gamers through the online store. If everything goes well, Microsoft might start releasing more of its games through Steam in the near future.

To play the Steam version of the game, players are recommended to have a Windows 7, 8, 8.1 or Vista operating system, a Quad core processor, 2GB of RAM,a Directx10 compatible graphics card, a version 11 of DirectX, and at least 2,550 MB of free space on the hard drive.

Here are the features of the game according to Steam:

- Epic campaign featuring 30 action packed levels with a brand new Halo story set just before the events of Halo 4.

- Command many of your favorite Halo weapons, vehicles, and armor abilities, and customize your Spartan to create the perfect Spartan warrior.

- Complete weekly challenges for XP and compete against your friends in Leaderboards for ultimate bragging rights

- Game supports keyboard/mouse, USB Cbox controller, and virtual joysticks for touch.

The 2013 version of "Halo: Spartan Assault" takes place during the events between "Halo 3" and "Halo 4". After a ceasefire agreement has been signed by the UNSC and the Covenant, a rogue Covenant faction attacks Draetheus V, the planet where the Spartans Sarah Palmer and Davis are stationed.

Gamers can choose to play as Palmer or Davis in their mission to thwart the Covenant from destroying the planet.