Great game! One thing that bugged me though, is that for some reason your wife doesn't help you at all, but just follows you around and does what you say.
Any wave in the game can be beaten by massively spawning spearman in one place, and then rushing them all forward. I even destroyed the endboss in one single attack without losing even 1 health. Make sure you put "push" as high as possible, and combine with attack.
If you have an elevator problem: build more NEW elevators, instead of making the ones you already have longer. A zigzag pattern for elevators works very well.