Okay, as I eraned the cheats by getting medals on all levels.(took a while), I noticed a few things when using the cheats during gameplay.
Some Glitches or secrets that you may not have known:
1- Each time you select "Gimme $10000" each other faction gets a surplus of income. Especially the ALiens when playing as the Preds or Marines; the ALiens gain HUGE ammounts of extra units without the need of hosts. I once clicked "Gimme $10000" about 6 times, and I watched the ALiens as I finished and they gained close to 20-35 extra units form what I could tell. CRAZY!
2- With the cheat "Invincibility", the ALiens (Asuming you play as a Pred or Marine) gain constant units without the need of hosts, for as long as you are invincible.
More coming......... (Post 'em if you got 'em)