SolarRocketshiptoMars! has just released a BETA packet for Co-Op Alien Defense, which can be found on their website http://solarrocketshiptomars.blogspot.com
It's been in the works for a few weeks and is just reached beta, at the end of the packet is information on how to send in feedback besides commenting on blog posts on the website.
"As soldiers of the planet Earth, you are to defend and learn from the aliens...But to do so we must attack."
In CO-OP Alien Defense beta you are given one of the three games modes (Defend), where you must defend the area from alien attack as they come out in waves from various randomized spawn points.
The game packet includes:
A players map,
A Spawn Map,
The rules packet includes a Paper AI, for the Aliens which seems to work quite well.
Goodluck and have fun gaming! You can also post feedback on this thread,...anything is appreciated!