I played Trenched yesterday at PAX East for an extended period in 3 player co-op with the art director standing next to me and Tim Schafer hanging out behind us. I got some details, too. It is 4 player online co-op. It uses the Brutal engine (from Brutal Legend). Whereas Toy Soldiers is a tower defense game where you control a cursor and lay defenses that in specific places, in Trenched, you can place defenses anywhere, and you are always in your "Trench".
The "tubes" or TVs that are in the monsters' mouths are the resources that you use to build new defenses. When you kill a monster, they come falling out. They are pooled between everyone. You have a magnet on your trench to draw the tubes in to your Trench from afar, and you can upgrade it to pull them in from farther away. All of the defenses can be upgraded, and he said it is slightly more beneficial to upgrade than to make a new one.
They didn't have a release date to announce, but when I asked him if they got anything from watching people play the games at these shows, he said that while they did, it was really too late to change anything. So it sounds as if it is just about done.
It played really well.
MS seems to be knocking it out of the park with XBLA this year.