Maybe it's not totally fair for me to review the series since I haven't picked them up in order. See, I pick them up from the library when they're available instead of buying (the price for each volume, as with most books these days, is a little steep for my broke self). Consequently, I get them out of order and sporadically and I'm not getting a complete picture of the series overall. But I can review what I have read and my impressions.
And just to be clear, I like manga, but I'm not a manga nut or anything. I can't keep up with western comics these days, much less what's going on in the Japanese comics scene. But I am a life-long comics fan in general.
The story was pretty okay. I enjoyed it, but there were a few things that bugged me. One, I think some of the script was kind of goofy and I think part of that was due to the translation, but I can't verify this since I haven't read the original Japanese. Many of the (English) sentences were awkward and this broke the flow for me. Two, I wasn't too hot on some of the silly humor. Personal taste, I guess, but I generally prefer a more consistent tone overall. The third aspect has to do with the art, which was good and less than good. Don't get me wrong-- the art was technically awesome in the individual panels. However I didn't feel like the panels always flowed well enough to convey the story smoothly and all the action was just too fast. I got a little confused at times.
But like I said, the technical aspects of the art was great. Especially if you're a gun geek and/or have a breast fetish. To be honest, the boobage here was just too much. I like breasts as much as the next hetero guy, but come on. Even the female zombies had enormous knockers. So while that appealed to the horny teenager deep beneath my horny adult exterior, I can't say that it helped me take the story very seriously.
Overall, though, it was enjoyable. I might not go out my way to read the rest of the series, but if I see some other volumes pop up at my library I'll be sure and pick them up.