Sol Survivor/Lossageus

In this campaign, the first four missions are immediately available.

Ridge pass

 * Win building only red heat towers
 * Don't lose any colonists

While the landing area is a good place for several turrets, there will be the occaional creep that slips through. As such, be sure you have a few powerful turrets near the colony.

The final wave consists of two Raveners. These are boss enemies, which will take a significant amount of firepower to destroy. When they pass, sell off any turrets you placed at the choke point, and try to rebuild them close to the colony. This should be more than enough to finish off the final boss creep.

Deadly Spiral

 * Upgrade only one kind of turret from your arsenal
 * Win building only yellow piercing turrets

There are five landing points, all which approach and merge into a spiral. In general, the third landing group should be merging just ahead of the first group of the next wave.

Downhill Battle

 * Don't lose any colonists
 * Win with Ignacio

There are four entry points within this level. On one side, the paths converge into a single choke point. On the other side, the paths will instead wind around, and will require placing more turrets to cover incoming creeps.

Paragon's Gambit

 * Win using a combination of only machine guns, pillboxes, and anti-air flak turrets.

Around wave 22-24, you will see Raveners. However, there is a more powerful boss in the final wave, the Zorast.

The merging paths will form a natural choke point. Building enough turrets here should prevent almost anything from getting through.

Crubicle
The ravener appears on Wave 21. This is then followed by a large number of gunships within waves 22-24. The Zorast appears on Wave 25. Behemok appears on wave 29. After this boss, there will be a large final wave of smaller creeps.
 * Don't allow a boss creep to leak.
 * Find the Forklift Seal (easter egg)

The best point of defence is in the central criss-cross where the enemies converge. By the time one-half of the wave approaches and is destroyed, the other half should be ready to enter the choke point.