i found it to be blah as well, the pathfinding is not so good, they tredge thru the water for ever..
There is no pathfinding. They just go straight no caring about what is in the path.
I liked it though it screams multiplayer co-op.
once you get to the later levels it's rather exciting. However one level, even on my decent system, chugged. This is because there was TONs of enemies on screen.
The other odd thing is there is no way to loose the game.
Also the game play is rather repetative, even as you get new technologies. Pretty much every level is like this:
Create Squads and engineers.
Use the Squad to blast the enemies, set the engineers to collect the souls to make more squads.
Setup a couple of officers to direct the flow of traffic.
Abuse the fact that engineers can travel over water to take control of buildings on other islands. (this fact made some of the later levels super easy)