Not sure what part of my previous replies gave you the impression that I’m not willing to change anything. I'm experimenting with adjusting the projectile collisions to collide with the worm bodies including bonus damage for "head" shots. I plan to go back through the early maps after that and adjust health and spawn positions. This is just a hobby for me so don't expect changes to come out daily, its probably going to take me a few weeks for these balance adjustments.
I did of course test the maps when they were originally made. It would take far to long to test all 49 maps each time i make a change to the AI or mechanics though. This is likely why some of the early maps have become far too difficult. Also i don't think i ever re-balanced maps when adding new maps to the same set so the difficult curve is probably sea-saws quite a bit.