Half-life 2: Substance is a reaaaaally radical redesign of the legendary gam who changed fps and we all loved. Still worth playing today, in our age of soulless games.
Back in the golden days of hl2 modding, this was something I played multiple times, and looking back at it, I sincerely wish I could go back for more :( The new additions to the hl2 campaign struck me with surprise and awe and the dozens of new weapons made the action tight and refreshing, with new additional monsters and player abilities to decimate them with. It's a shame this only partially works with mod fixes following the may 2010 update. Perhaps someone with some free time on their hands…