I bet the first wave is result of this little bug; which shouldn’t happen. That is about the only thing I can really say on the matter, as from the description it seems sound enough that is what happening. that and I don’t really play on that mode, so it is good to get feedback on it, especially when a bug like that happens and the devs can figure out whether it is suppose to do that or not… Or well was intended or not.
the rest is far as I know a more military focused playthrough from what I gather, since you’d need a good bit and that kind of mindset from the beginning. Yes there should be more waves, but not all at once in the beginning; there still be needing a balance somewhere. That much I do agree, especially if I was ever to attempt that mode of play. 