actually the level pack a was troublesome some years ago when i tried. but if you beat the first game first(easy game) it becomes clear what you need to do.
move slowly killing one enemy at a time. don't take huge risks. money can be spent at shops that I believe(could be wrong) works as checkpoints. Use missiles. keep on moving when they aim at you and look for safe spots.
"The mamooth"? really? "I still don't how you see the stealthed units" shadows and show themselves while shooting. "armored goliaths" easiest killed with basic gun... wut? intro showing a big city that I have to defend. actual game... I am the only gunner alone with some girl with enemies coming from wasteland-like territory. Army of destruction? Me and a girl makes an army? The enemy are the army of destruction? Single medium badge less awarded and by me considered harder than a lot of hard badges? Check. Domes which you thought was gonna do something but was just extra armor? Check. I don't get it, developer.
Box clever level pack: This sounds like an intelligent game. Ah with fancy monocles and hats and stick the character looks sophisticated. Level solution: Stand on tower, topple it while jumping off. Or just fall right and avoid the spikes on the right you see the last second. Why is this called clever again?
I am starting to think the dibbles are completely convinced they go to heaven ? I mean use their death to do a good deed and sacrifice yourself to end the pain and go their God/Nirvana or something. That is my only explanation.