The ability to heal or even revive units in a tactical game has a very profound effect on how it plays. In a game like Hero Academy if your healers die you are more than likely going to lose the game, as losing the ability to keep your troops standing (and fighting at full capacity!) unless they have been totally annihilated is often too big a loss to make up.
This mechanic in Hero Academy (amongst others) leads to a system where moves are plotted based on whether a unit can simply survive a return attack. Damage short of death is relatively irrelevant given how easily it is removed and how it does not affect the fighting ability of the unit itself. It’s like Dungeons & Dragons where your character can be shot up with arrows and hacked apart by swords, but they are completely fine until the moment that they drop to negative hit points and suddenly they are incapacitated and dying.
Obviously this level of abstraction has its purposes, the primary one being simplicity. Any gamer can tell you that the more complex a system, the more things can get bogged down. So the question always becomes: what’s more important, realism or playability? Striking a balance between those two can make or break a game, and (unfortunately for designers) players have different opinions on what the correct balance should be.
Diesel Tactics abstracts squads out to units of generally 3 members. While this adds a bit to the complexity of the game (as opposed to having 1 character to represent 1 unit), it adds a lot to the depth of the game. When a squad takes damage its members die. This means that the unit has lost combat effectiveness as its ability to return fire has dropped, as well as its overall survivability. You could think of this as a simple way of abstracting that single character from Hero Academy or D&D into 3 levels: when you take a bit of damage you are now operating at 2/3 capacity. Visually, one member of the squad is gone, but again it can just be thought of as a single entity that has lost effectiveness as it lost hit points.
Getting back to healing (I think that was the original topic, it was so long ago now…), Diesel Tactics will not have any of that. Any damage that you inflict will remain, and any casualties that you take are permanent. Using cover and smart maneuvering is key to victory, and players will have to think of the actual relative danger of moves that they make. Rather than being able to ask a simple binary question of, “Can they survive if I move them there?” they will need to ask, “How intact will they be if I move them there?’