Invaders.zip contains v1.0 of Space Invaders for Pilot. I wrote Space
Invaders for Pilot as 100% freeware; I encourage its free distribution.
In order to install Space Invaders on your Pilot, follow these steps:

1> Go to your Pilot software installation directory
2> Start the app "instapp.exe"
3> Hit Browse... and select Invaders.prc, which is part of Invaders.zip, and
   select "Open" to dismiss the Browse dialog.
4> Select Install...
5> Place your Pilot in the Pilot Cradle, and press the Hot Sync button.
6> Once the hot sync completes, Invaders is installed!

Enjoy!
-Pilot Hacker