So basicly everything this does is that it will play the "WOOOW" sound effect everytime you get a kill.
Nope, this program is 100% VAC-FREE. Everything that this program does is just getting info from the client if it get's a kill, this is done with CS:GO's game state integration. Game state integration is tool that CS:GO developers have done for community. Here's more info about Game state integration: https://developer.valvesoftware.com/wiki/Counter-Strike:_Global_Offensive_Game_State_Integration
Everything that you have todo is to put the "game_integration_woow.cfg" file to your CS:GO cfg folder. It depends where you installed you're CS:GO, if you installed CS:GO to the default install path, then it should be here: "C:\Program Files (x86)\Steam\steamapps\common\Counter-Strike Global Offensive\csgo\cfg"
Then just start the program and you are ready to go!