1-5 is very interesting and fun
6-15 kill all the zombies with no problems. It is interesting only to find new weapons and the emergence of more powerful zombies (yellow, blue, green suits)
15 -.... very boring. The best weapon, the waves of zombies do not cause problems. Car repair is slow.
I think you need to do a wave of attacks zombies 2-3 times shorter. this will speed up the gameplay and adds interest to the late game.
P.S. Sorry for my bad English.
Congratulations! You just won the Momentum Mayhem Master Badge and 30 points!
Wave 30 completed – "Progress" indicates level reached, not level completed.