I've compiled a version of CS that mimics the beta versions of gameplay.
There 140 maps, most of which weren't included in the final ver, but these were maps you would find being played during the 1999-2000 era of CS.
Alot of sound's have been replaced by there old ones, particularly the weapon sounds, some radio commands have been changed back. And the Player models are based of Beta 7.1.
Both versions of the M4A1 are included!
Download Instructions: Just extract the folder into your steam/steamapps/accountname/half-life folder.