Is this site safe to download from?
everyone is given the same key
Also your graphics drivers have these features built in for basic recording (and on-the-fly transcoding). Radeon ReLive or Nvidia Shadow Play.
If you are on windows 10, you can press windows key + G to enter the game mode and you can record anything on the screen.
IMO, just use Open Broadcaster Software, OBS. Completely free, it's what a lot of streamers use to broadcast to Twitch et al, and it has a local saving option.