If you are struggling in a certain zone against certain enemies, there is a way that you can abuse the zone transitions to get a huge advantage. It goes like this:
1. Focus all of your power using every tool to kill a single enemy, but hang near a zone entrance
2. After killing the enemy, retreat into the next zone.
3. Recharge your shields, psi, health, grenades, etc.
4. Save
5. Go back into the zone with the enemies, and go to step 1 unless all enemies are dead.
This offers a couple advantages:
* They will remain with status effects when you next enter the area, so try to fear, fire, freeze, etc. them before you leave again.
* You can recharge everything you need in between each enemy
* You can save after killing each enemy
* You can apply buffs like food, morphine, adrenaline, etc. before initiating on each enemy.
And one disadavantage:
* It looks like you take a -10 penalty to initiative when you do this. I'm not sure if it's a byproduct of another mechanic or intended just for this.
Even with the disadvantage, this seems extremely powerful so I thought I'd report it in case it was unintended.