What material are we missing? I think there's plenty enough, not even counting the community's contributions. The only time I would say HL is missing content is in relation to
- Maybe a comic, which isn't a possibility since the guys doing the 2008-9 era Valve comics probably don't work there anymore.
- Episode 3, which is now a pipe dream that only the community can parch.
- Another HLVR game which'll never come.
- HLX which at this point is a certainty.
3/4 of these are unobtainable, and the only that IS is the one that truly matters.
Also OP4 being the best thing to come out of the series? Really? Good sure, but c'mon man, the Episodes are far better.