Mike & Pete's Half-Life Sound Pak (aka MPHLS) is a mod for Half-Life 1 - the original game that was released in 1998. (MPHLS is only slightly younger than that.) Thanks to Hickadam & Pumpkin_Masher, you can now enjoy this mod on Half-Life:Source!
The installation is, unfortunately, a completely manual process. But don't fret: each step is very straightforward, and fully documented with the the included instructions.Download links are available from our official website