Now I remember why I hated the original.
The only way to get past some levels, IE the 24 virus spawned one, is to either get lucky or have the hands of a god. Sitting there spamming cells as fast as I can only to have all of my units wiped out is NOT what I consider fun or challenging.
The music (tone deaf?), the rule of 'if it goes off screen it immediately dies', the poor upgrade system that you cannot grind out should you be having trouble, all contribute to a poor playing experience.
Overall the idea is good, but the final product was poorly done.