I saw this awhile back. I was impressed with the demo; it ran pretty acceptably even on my ancient netbook, and the art looked really good. I wish you luck with your indiegogo campaign. That being said, a bit of constructive criticism.
1. You should have a few pictures up. Your video is good, and video takes priority, but some screenshots would really liven up the page.
2. Your goal is, honestly, a little high. It really shouldn't be, but the industry is what it is, and there have been many games on kickstarter/indiegogo that had to struggle to raise even a few thousand, much less 15k. Most of those which raised more were by people with established track records and fan bases, or who came from the industry and thus have contacts in media, with other developers, etc. to promote their project.
3. You might want to reconsider your title. It kind of ludicrous at this point in time, but the F-word (even obfuscated) is still somewhat stigmatized and might cause you some problems reaching a younger set. Especially considering that the context sounds a little suggestive. I know it's a zombie game, and your zombies explode into gorebags, but frankly, with your art style, it's really not M-rated stuff, so I wouldn't discount that market. One idea:
Grandma vs Zombies: A play on Plants vs Zombies. Simple and to-the-point, sounds 'familiar', but also a little different, humorous, and intriguing.
Badass Grandma: If you want to capitalize on the 'badass grandma' aspect, and downplay the zombies (there are a lot of zombie games...)
4. You might want to refine your copy for your campaign. For one thing, the english is a little rough around the edges. I don't mean offense here, but it is what it is. Also, some of your language and proposed features are described in a vague way that implies you don't quite know where the game is going. This might not be the case, but you definitely don't want to undermine the confidence of potential contributors by coming off that way. Promise less, deliver more is the best approach.
5. I do not know if this is possible with indiegogo, but if you could embed a demo of your game on your indiegogo page, you should. Most games on kickstarter/indiegogo are basically just pictures and videos and a lot of jaw-wagging. Having a demo right there would make your game stand out, and make your project look more serious. The demo I played a couple weeks ago looked very slick, and made a good impression. You should hit people with that right off, if you can.
6. You should target mobile. Period. Your game would control fine on mobile, and the performance seems quite good even on my weak netbook, so you should be able to scoot by. There are some definite headaches/limitations with mobile games for C2, and there will probably be a lot of devices you won't be able to support, but you should still go for it. Desktop is a much harder market, as the competition is more fierce, and there's less cash to go around. Of course, there's no reason not to support desktop too...but mobile should probably be your priority, if possible.
Wish you well with your project, hope you find some of that helpful.