For those who have yet to experience 2010's hollow hit first-person shooter, a Halo: Reach demo is now available on the Xbox Live Marketplace. The 1.74GB download offers snippets of both the campaign and multiplayer. As a bonus, there's $20 off the full game through Games on Demand for the next week.

The campaign mission 'Long Night of Solace' will see you and Noble Team fighting to reach a launch facility, then blasting off into space to take on the Covenant fleet, complete with spaceship combat. You can also play the mission in co-op over Xbox Live and split-screen, though it won't support matchmaking.

Xbox Live Gold subscribers can also play Reach's multiplayer modes Free for All Slayer and Headhunter modes on the Powerhouse arena, plus co-op Firefight mode on the map Overlook. You'll only be able to play with other demo players, though.

As ever on Xbox Live, for now the demo's exclusive to Gold subscribers. Typically, exclusive demos become available to all after a week or two.

If you take a shine to Halo: Reach, you can pick it up cheap this week through Games on Demand. Until May 30, a downloadable Games on Demand copy will only cost you $39.99--down from $59.99, and a good $10 cheaper than you'll find it in many stores.

Released in September 2010 exclusively on Xbox 360, the prequel to Halo: Combat Evolved was creator Bungie's last game in the series. Bungie is now working on a new cross-platform property, to be published by Activision.