It's best to only use the sniper when you get ganged up by zombies. One sniper shot penetrates through multiple zombies, so a sniper can help you clear the danger area very quickly.
When there are a lot of zombies next to you, one/two sniper shots can clear all of them ;)
It would be cool if the Ai had an actual laid out path, so skill and timing would actually be necessary. It's really inconsistent that some levels are nearly impossible to win, then you restart the level and it's a piece of cake
It's best to only use the sniper when you get ganged up by zombies. One sniper shot penetrates through multiple zombies, so a sniper can help you clear the danger area very quickly. When there are a lot of zombies next to you, one/two sniper shots can clear all of them ;)