Hmm... you have four stages ahead of you, which we have already completed... :)
You just joined us, if I'm not mistaken...

Download the starting saves and maps, play through them, and compare your results with those of the leaders, without reading the Walkthroughs beforehand...

And, to be honest, I have another extra-class blitz map (unfortunately, I'm not the author :D), which only a few players have managed to complete, out of those I know... Maybe I'll offer it as an unofficial bonus for everyone who wants it after the fifth stage of the blitz is completed... Maybe... We'll see...