the game should allow players to buy or build whatever they want.
free playing as existing is fine, no rewards for game levels.
game levels to buy each type of corp needs to make sense, such as lower game level corps should have fewer workers than higher game level corps. at the moment, seem just random choice of which corps belong to which game levels.
civilization has progress development, so game levels should at least follow that. that is you can't build a nuclear weapons corp if you have just so many farmers in your country (nothing against farmers here okay

)
lastly why would you want nukes to fight with other players or c3 anyways? nukes are too expensive and too much requirements.
just stick with your airforces, landforces, navies, special ops, etc....
there are too many military wares in sc already, just look at the product list....we need more food products in sc