Another point of conversation when designing the game was how to health system will work.

Fairly early on we decided  that they player would have a limited amount of health. Players felt dying in a single hit was unfair and frustrating.

The number we decided was fair was 5 health points.

There was also the dilemma in considering if the enemies should sometimes drop health packs, the same way they drop ammo. After testing we found that this  just made the game too easy and removed a lot of the challenge. 

We opted to go with a few points on the map that would have health pickups. Another benefit of this is that players are then rewarded for learning the map layout.