I did think that it was a very well done game. I do think, however (as others have said) that it did also leave a lot of room for improvement.
1. I think the firing accuracy and recoil were fine, but at the same time I think the zombie movement speed was a bit fast. Approximating the distance (by zombie height) it is at least 200 feet to the corn field (by the barn it is at least 1000 feet, which would just make the zombies crazy fast). Which is a reasonable distance. That, however puts the slow zombies moving about 2-3 miles per hour (about as fast as a normal person walks). The fastest zombies run, however, at around 20mph, which is faster than most living humans can run for any extended distance (though the world record human land speed is at 27mph and it is estimated that a human body could run as fast as 40mph without destroying itself, but that is theoretical). Which, given you had unlimited ammo was I feel a necessity in adding difficulty to the game. But the speed did seem a bit excessive. Balance is a good thing (so not a main thing, but it is a thing).
2. I agree that the grenade launcher was severely under powered, but due to it's fast reload and multiple hits, it was also the most useful weapon in the game (IMHO). Although the recoil on the other weapons was acceptable, it also made them fairly useless and my base always suffered damage (in the later levels) when i bothered to use them.
3. Time taken to search? The number seems rather arbitrary. If it is in minutes or hours (which isn't possible given the course of the game) the value seems like more time than someone in this situation would spend on a search (600 minutes = 10 hours). And in seconds it is way too low. What I am left wondering is simply why have that figure there at all? If you look at similar games you simply have a certain number of hours to work with any given day, you can choose to use that doing repairs, searching, or resting (doing nothing). The idea that you can 'build up' free time is just odd to me.
4. I also agree with others that the concept of being able to give 'found' weapons to other defenders would be a good thing. Instead how fast they fire and how accurate they are depends solely on whom is in your defense stock, it does not seem to matter that you have several automatic weapons just setting about. Definitely one to consider for the sequel.
5. I also agree that a change of background/scenery would be great and make sense to the game each time you moved on.
6. Even though you had different types of zombies (which is always nice) there wasn't a great deal of different zombie skins. I.e. it always looked like the same group of zombies. Which is understandable given that it is a game and resources should be conserved. But at the same time it is always nice to have that extra variety. Even if it is just a few different colors here and there.
7. Even though there was talk about search parties, and search skills, and ambushes, even when one had a good search party, they would often come back missing members and empty handed. I don't know how that is calculated, and it wasn't really integrated well into the story. I think more could be done with that in the sequel as well.
As I said though, it is a very good game. I don't want you to think that my comments mean otherwise. I thought the look and feel the game, zombies and guns, was great. But there are always things that could make a game even better. I have read some of the reviews and I think there are many good suggestions in them. I really do hope to see a sequel that takes many of these into account.
Keep up the great work, I look forward to more by you. 4/5 and 4.5/5 (or 9/10 because I liked the old system better)