2K Games in conjunction with 2K Marin and Irrational Games have released their first DLC pack for Bioshock 2 aptly named: "Sinclair Solutions Test Pack". Wholly for the multiplayer element of Bioshock 2, this DLC contains:
Aimed at prolonging your multiplayer experience the above elements certainly do that, but there is no secret that the numbers on PSN or Xbox Live for Bioshock 2 multiplayer are limited.

Oscar - Very Debonaire!
The masks are a nice touch, but in the heat of battle, they are not really noticed all that much. The additional weapon upgrades are a welcome addition allowing you to customise your payload to suit your tastes.

Louie - The stripes suit him
The added characters have their own distinct personalities which add to the atmosphere Bioshock 2 builds, which crosses over quite well from that of the single player experience. Their melee weapons are nicely suited also.
Unfortunately due to the lack of availability of joinable multiplayer games I am unable to report on the additional higher level trials that have been added.

Oscar kindly modeling one new mask
Verdict
One for diehard Bioshock 2 fans that have enjoyed the multiplayer experience and are looking to extend that joy. If you have not enjoyed the multiplayer, I would await the single player DLC slated for release later this year.
- klevster aka cody