This is a genre that I tend to love. I wonder if this is one of those games where one person worked on it.
I wonder because there are so many things that could've made this game so much better than it is. It really could've been something. Nearly all of the features are irrelevant.
Instead, it is the most tedious dull grind ever to try to finish the achievements. The gameplay is beyond easy but like I said tedious. Leading to you dying because after hours of play, you just can't help but try to find some more shortcuts and end up paying for it by a death out of nowhere because of how the damage scales up so high.
I finally thought I had it down and died in wave 35 with just about 900,000 spent. I can't see myself bothering with this again.