The shareware episode of Raptor: Call of the Shadows, for DOS. In this game you shoot up the planes that are worse than yours and take their money and...
The came is divided into three sectors, giving you some new enemies and scenery in each: Bravo Sector, Tango Sector, and Outer Regions, with 9 levels in each region.
The first episode, the Bravo Sector, is largely urban/jungle, ending with a large enemy oil rig.
Tango Sector, the second campaign, includes some more variety including a chemical plant, farms, city environments and an airbase. In the final episode, Outer Regions, the player travels through moons, ice worlds and volcanic wastelands. The last two sectors also have a “night wave” where you fight at nighttime, adding to the game’s detail.
The Bravo Sector is the easiest of the three, and it allows players to save up money to weapon and shield upgrades to fight effectively in the other two campaigns later.