I've found that if you can't unlock the last few tiers of weapons, try repeating all stages. And as for the bottles not breaking, I find that ensuring the "Screen FX" option is on is the only way to get mine to break. Still can't unlock the last pistol, though. :/
Good game, decent ending. Level 19 I actually used a real strategy to get past, but level 20 really felt like a cheap way to make a challenge. Other than that though, great game, 4/5.
Very good game, but, as has been already said, a bit buggy. Also, I didn't like the fact that you can attack with a creature as soon as you play them. Not that big a deal, but it can get quite annoying.
Man, that was a perfect ending... The last day before I got to Union City, at the very end the zombies busted through the barricade, right as daylight broke, and I just finished 'em all off with quick headshots from the hunting rifle... Just like a movie ending.