Ever heard of mech warrior or mech assault?
Well, this cam out in 1999 just after mech warrior 2 it's an rts game where you can organise weaponry and pilots for you mechs to complete missions, if you get mech commander gold it comes with the expansion campaign and a mission editor, there are also turrets and points of interest you can capture so the turrests will work for you and the gates wont open for enemies, its a really fun game.
Also, if you cant get your mechs to the turret control without them being blasted to pieces, just air strike the power station and shut them down altogether.
You earn credits by minimising damage and pilot deaths, destroying enemies and liberating salvage during your missions which you can then spend on better pilots/waepons/mechs.
I only have the original, there are like three out at the moment.
8/10 game in my opinion.