Core Online service. Sniper Challenge, if you remember, was a pre-order bonus for Hitman: Absolution.
What both games coming to Core Online does alert us to are changes to the service's payment structure. It was originally completely free-to-play, albeit with intermittent ads. However, free play is limited now to 20 minutes each day (still with ads). At 20 minutes a day, it's going to take about a month to complete Tomb Raider: Underworld.
You can pay $2.99 per month to get full access to Core Online's library, which at present includes Hitman: Blood Money, Hitman: Sniper Challenge, Gyromancer, Lara Croft and the Guardian of Light, Tomb Raider: Underworld, and Mini Ninjas. Alternatively, each game can be bought individually for $4.99.