Meanwhile, I've been working through Taxing...
17: By building up to the top, you can get through with one basher. So far I haven't been able to eliminate the last builder, but I just thought of something...
25: 3 builders, thanks to my patented "slingshot" technique (at least that's what I call it
). Replay attached, although this is
much easier than previous solutions that use this trick. Bashers and bombers are fairly easy to eliminate individually.
26: 5 builders. I thought I posted this replay somewhere, but I can't find it on the forums, so here it is.
27: It's been shown already that the bombers and blockers can be left. Whichever route you take, it seems you need 6 builders.
30: 7 diggers (and 9 diggers for Mayhem 11)
Taxing 23 and 24 can be taken straight from the minimum skills topic, since both of those only give you builders...
That would be 12 and 5 builders, respectively.
Mayhem 13 can be done with 1 builder. I've tried for ages to find a no-builder solution, but it just isn't working for me due to a lack of diggers. You can also beat this level without using any climbers, floaters or bashers.
I tried this one a while ago while looking for "no-builder challenges", and came to the same conclusion.