Good idea but not so go realization
All is fine till later on when all becomes the same and i ahve loads of money.
Need to make guns and stuff upgradable.
Suggestions:
Upgrade weapons vs certain type of bugs (several different upgrades)
Upgrade rate of fire for certain type of soldiers (again several)
Upgrade rate of fire for moratars
Upgrade range of miniguns
Maybe make heavy guys have melee attack vs bugs when they break in dealing lots of dmg
Ability to spend money for rebuilding walls/twers
Ability to make new towers and maybe walls (base expansion)
New uni maybe (sniper, flame thrower, medic)
Grenades for light infantry
Ability to buy traps or set explosives
Ability to walk out of fortress so u can use ALL of your soldiers (snipers could take cover on rocks or something so they would be stealthy)
Some new insect then maybe if u can get out (antlions, some insects that burrow and get out of the ground to get ur outside soldiers, sonars for detection of underground insects...)
Well thats all i can remeber now :D
I wanna see 2nd part of this game.