Nah, the simplest way is to produce clubswingers. In fact, the only two units you have to produce in the game are
1. Club man
2. Super Soldier
All other units simply need not to be there. You'd better-off producing none.
I'm talking about "impossible" difficulty.
.
Strategy:
At start, wait until there are 4 enemy clubswingers on the field, use special, and use the money to build egg thrower.
DO NOT UPGRADE THE AGE. The stone age can last you until modern assult rifles come out. Just use the money to build more tower spot, and put primative catapults on them. You have 3 catas and one egg thrower, the enemy may push in your front, but they can never break a clubswinger wall. Just mass produce the clubswingers non-stop. Use special to kill enemy ranged units.
Enemy at modern age, the clubswingers can still hold off melee units. When more then 2 rifle in-line come out, quickly advance to modern age directly and build 2 dual-cannons. Your cannons will decimate everything as your clubswingers run out, none can reach your base. No units needed to be produced.
Advance to max age asap, build 2 lasers, then replace the dual cannons with 2 ion cannons. Wait until you have $600,000 and make 4 super soldiers. It's over.