You can download the full version of Genetic Species from the Aminet:
The game itself is arse. It did not work on my towered 1200 with either an Apollo 060 or Blizzard 1260. I got it running in WinUAE, but it really wasn't worth the hassle. Stick with AB3D for the definitive Amiga first-person shooter. If you want something more advanced, go and grab a copy of ADoom (030 machines) or Doom Attack (040/060).
As for T-Zer0... It's a shoot-em-up. Exactly what you'd expect from that period of Amiga games, ie. it looks okay, if you like pre-rendered raytraced graphics, but plays like a public domain game.