Plants vs. Zombies

I am not much of a gamer so I didn't really get into the animated zombie attack on my house thing. I made it to the round where the neighbor guy came over and spoke gibberish but there was a conversation bubble for me to read. That was pretty funny! I found the game sort of frustrating in that you had to wait for some of the options to recharge before you could use them again and that there was no clear end to the game...how many levels are there? Is there a way to win the game or do the zombies just keep coming back? I did appreciate how intuitive it was to play and that each time a new plant option was added I got a little explanation of what it did. However, I did find the sound effects pretty annoying and the fact that I was being attacked by groaning zombies was annoying in itself too (I have never been a fan of whole Zombie thing). I did find myself wanting to know how to win the game but decided after 25 minutes or so that I wasn't going to invest any more time in finding that out. Overall, interesting experience but probably will never play it again.