You kinda like can say that the missions are like a campaign since you cannot jump scenarios, you have to start from the tutorial and then go from there. And yes, its basically "enemy has X ships, go get them" kind of style.

Although some scenarios are special in the sense that due to spatial anomalies they disable shields, halve range or speed or limit the amount of modules, stuff like that.

Thank you for an informative review. Keep em coming. I am playing Defense Grid Gold at the moment. It has similarities in that the gameplay is simple (one might wish for more stuff to do), but still addictive.