Good morning all! I want to make a game where certain units can combine forces to become more powerful. The way I see it, two units can increase each other's powers, but if one dies, so does the other. To add to that, I also want to allow three units to have the same effect, only more powerful. However, I need a steeper price for them to be able to do this as well. Currently I'm thinking that this triple threat ability will make them immensly powerful, but only for a short time, in which after that time they all die. Anyone here think this might be a good idea? If not, what might you suggest instead? I want the player to think twice before blindly combining three units together.

How expensive are units? Ultimately, it all depends on how easily and readily units can be replaced... if units take hours to train up to being decent, combining into three would be near useless; yes, I could beat a boss, but i would three guys I spent hours training.

By contrast, if units are incredibly easy to acquire, and I expected to lose them anyway, combining would occur every combat.

Are you going to implement any way to counter the "more powerful" effect other then the costs? If not then don't bother with this.

Here's an example, a single unit with power rating of 1 if combined with another unit with rating of 1, becomes power rating of 3.

If the cost of combining the units is below the cost of 1 unit, everyone will simply combine all their units when they are built. If the cost of combining the units is above the cost of 1 unit, no one will combine their units unless it is absolutely necessary.

My suggestion would be to give unique powers instead of simply boosting their power and something more then initial setup costs as a way to balance it out. Maybe some weakness or upkeep costs.

A very good example will be Starcraft's mutalisk when combined they became very strong long range air-to-ground attacker, but it makes them vulnerable to enemy air units as they have no air-to-air attacks.

The starcraft Mutalisk can't combine, and has an air to air attack. You're thinking of the guardian, which is an upgrade. A better example would have been archons: they're made from two high templar merging. High templar are a caster unit with no attack, archons have no spells, but an extremely powerful melee attack and lots of health.