Hints:
If more than one unit gets killed during a mission, go back and replay it. The later levels get extremely tough, and you can't afford to be fighting with a partial squad.
Make sure to let weaker units get some kills and build up their experience points too, otherwise you'll have weak links in your squad.
When in doubt, play defensively. The mutated Scay'Ger are aggressive, and will usually come to you. This should let you set up your units in effective defensive positions.
Rotate units on defense mode. Although it's a great way to defend units, if done too often with the same units, their guns will heat up. Take turns with the positioning and defense mode.
Move your units in small groups, rather than solo ventures. This way you'll be able to have multiple attacks on Scay'Ger.
Don't be afraid to experiment, the 'undo last turn' button lets you quickly go back to your last turn (unless Bratt or your last unit is killed). Sometimes you'll find a new or better solution to a difficult area.
It's a good idea to close doors behind you to prevent the Scay'Ger from attacking your backside. (The mutations have affected their intelligence with doors and switches).
Sometimes the difference between victory and defeat is a single step. Resting your units or taking stimulants at the right place can make the difference.
Use the magnifying glass to get information on unknown Scay'Ger. Often it can reveal a weakness or defect.
The closer you are Scay'Ger, the better your odds of defeating them, since accuracy decreases with distance for most weapons.
