MINERVA, by Adam Foster, takes you to a remote island under the control of Combine forces. Something is going on here. Your goal is to uncover what that is and destroy it. Oh, yes-- and try to survive.
This is the newly released 2013 edition of the famous Half Life 2: Episode One mod.
Runs pretty good with Hl2 MMod as well. More stuttering the Half-Life 2 but still great experience and has less bugs than configuring it to work with the native Half-Life 2 version.