combinations of Upgrades:

what can the units do fully upgraded.

7 upgrades

Speed

HP

Weapon Fire Speed

Missile Speed

Missile Range/missile life

Missile HP should this be one? I can have missiles regenerate -1 hp over a certain duration, and increase that duration with range. If a missile has a lot of hp, it will go very far...+range means very very far. And won't be destroyed as easily.

Everything doubles. So thats lvl 0 X2 = lvl 1 X2 = lvl 2 X2 = lvl 3

So 1X2 = 2 X2= 4 X2 = 8.

Or +2 +2 +2 = 7.

Or +1 +1 +1 = 4

Using a system of 3 levels that is in equal increments. Then we just find out how much speed =1 damage. 2 damage, 3damage, 4 damage.

How much range = 1, 2 ,3 ,4

The first time, it doubles. thats no good.

1, 1.5, 2.25, 3.375, 5.06

Still this is not right, as you get further, your upgrades so more. This can be used to be uber.

3, 4, 5, 6 now it get's weaker. Or does it?

Perhaps number do not matter as much as testing. Finding out exactly how much range = how much damage.