A couple issues I had with survivor mode:
-The extra lives are smaller than my thumb, so sometimes I'll miss and lose my combo
-Same with the copter button, sometimes I'll miss it when I'm in the middle of an intense game
- Sometimes, however, I'll try to shoot at a red cat and accidentally hit the copter button
Sometimes this would cost me the high score, which was pretty frustrating at times.
Other than that, I find the survivor mode to be really addicting! I challenge you all to beat my high score.