Offshore offers a multi-level side story of Gordon Freeman while en-route to City 17 via Highway 17 in the Scout Car.
I discovered this only just now... Its length is pretty long. Like the longest HL2 mod I've ever played, apart from Black Mesa (evidently). Level design is well thought out, following a certain theme that is constant throughout the entire mod. Get ready for some high octane action because Offshore is chock-full of it. You will be fighting more Combine soldiers then in all other mods combined (a rough estimate, but you get the idea). There's only one thing that bothered me. In a walk-through I read the only moment I could get my hands on a rocket launcher was at the start of chapter 5. I somehow missed that and played the remainder up until chapter 7 without one. I wondered why there were so many rockets lying around and never a rocket launcher. Then I came upon a battle where one is absolutely necessary to destroy a gunship and progress. Seems like an oversight not to the give the player one at this point. So I had to spawn one with a cheat. That's basically the only negative thing I have to say about Offshore, because it flat-out rocks !!