Cheat menu
To unlock Cheat Mode, pause the game and press R, R, L, R, L, L, R, L, R, R, L, R, L, L, R, L. Now, a number of Cheats will be available from the Options menu:

Cheat Win
Clear Fog of War
Enable All Levels
Gimme $10,000
Player Invulnerable
Show LZs
Toggle Unit Spying

Predators
Try sneaking up on and attacking a lone enemy with a cloaked Spear Master and see what happens.

Aliens
Bring several drones along with any hunting parties. You can use them to drop hive nodes as you move along, enabling you to regenerate any units that become wounded by enemy resistance. Moreover, hive nodes see just like other aliens, enabling you to track any enemies that cross your prior path. Finally, if you upgrade your drones, their cystic acid spittle ensures that any hosts you subdue will produce offspring of stronger stock than normal.