I know this is impossible... but i have always wanted to play a game with a story line that changes with you... lets you make the decsion on whane and where to fight...

With that said if you win good... move on to what you want to do... if you lose, have a new scenario with a defeat theme.. Basically hide out rebuild start off in a new level... not replay the same level until you can find out how to beat the level...

So if your main goal was to ultimately defeat the zerg... say you lose move onto a level where your rebuilding and in a later scenario... go at it again... let the battles you win or lose decide where you end up.