Marathon: Durandal and Spyglass Board Games are now available on the Xbox Live Arcade, as previously announced. Marathon is an old-school FPS originally developed by Bungie, the guys behind Halo. While you may not have had a chance to play it before – or even hear of it – it’s a game that introduced many mechanics into the FPS genre that have been taken for granted for years now, like dual wielding. The game will run you 800 Microsoft Points, or $10. If you liked Doom, be sure to give Marathon a shot.

Spyglass Board Games is a compilation of four very popular classic board games: chess, checkers, mancala, and reversi. Given its cheap price (400 points; $5) and Vision Camera support, it’s definitely something worth picking up if you enjoy any of the included games.

Check after the break for more details on both games.

Marathon: Durandal:

Seventeen years ago, you survived a vicious Pfhor assault on the U.E.S.C. Marathon. Now you have been awakened by the enigmatic, sentient A.I. called Durandal and sent to an alien world to uncover the mysteries of their advanced technology. In Marathon: Durandal, armed with only a pistol, you are humanity’s last champion!

• Epic story: Exclusive to Xbox LIVE® Arcade, Marathon: Durandal is a cult classic first-person shooter (FPS) that continues the tradition of great gameplay while remaining faithful to the spirit of Bungie lore as the predecessor to the Halo franchise.
• Upgraded visuals: All images in the game have been redrawn in high definition. 
• Modern networking: Marathon: Durandal features a new modern networking layer built with Xbox LIVE in mind. 
• Superior control: The redesigned controls take full advantage of the Xbox 360 Controller and enhance playing a first-person shooter on a home console.

Spyglass Board Games:

Spyglass Board Games offers a fun new take on classic board games, like Chess, Checkers, Mancala, and Reversi. Play and chat socially on Xbox LIVE®, or play against the computer. Use the Xbox LIVE Vision camera to personalize the game board, playing pieces, and video effects. Each game has custom pieces to choose from, such as a rook made of stone, or a furry checkers piece with cute gleaming eyes. Make each game your very own!

• Full featured games: Four classic board games to choose from. Play Chess, Checkers, Mancala, or Reversi.
• Video integration with Xbox LIVE Vision camera: Fully integrated video chat lets you see your opponent. Use the video effects to personalize your game.
• Customizable pieces: Choose custom game pieces that range from traditional marble, to metallic silver, to fuzzy and wiggling gel.
• Twelve achievements: Twelve achievements are offered ranging from easy, such as playing all four games, to more challenging, such as taking all four corners in Reversi.