My overall opinion of the game: excellent! The perks and item store are very diverse and give you lots of options. Definetly makes the game more interesting/increases replay and gameplay time. However, I do have some critiques and errors. All throughout the game, I would always try to click 's' to duck. There is no duck/squat in this game! For a large part, projectiles are aimed high and would be easily dodged by ducking. Although there are many ways to dodge such projectile, ducking would often be most efficient. Secondly and finally, I'm pretty sure that it's not a running speed/computer error, but weapons such as the Quick Silver and Big Kaiser do not shoot in succession well at all. The Quick Silver will shoot, then after clicking multiple times, will only shoot after jumping or switching weapons. The Big Kaiser has the same problem. Otherwise for those few errors, it's great! I can use the chainsaw and twister in leu of the two buggy weapons, though, it would be nice to use them.
Actually one of my favorite games of this genre...considering that I'm not any good at any of the other similar games... Regardless, after upgrading everything, even after fully upgrading sniper, it was quite easy to play. I found myself almost always aimed at the ememy spawn area. Otherwise, before everything was upgraded, it was very fun and enjoyable.
Fantastic game, overall; however, I can't seem to find the "Load game" button after saving. Also, after the computer makes all it's moves on Chapter 8, it takes quite a bit for it to end its turn. That's the only level I had problem with, though. But, really, a fantastic game.