Thank you for playing and the great feedback.
I really should make it clear in instructions about killing bad guys is good, killing cows is bad and that there is just a fixed amount of both.
So the cows and the bad guys are both distributed randomly over a set length at the start of a game (roughly worked out to be the length of the music). However, I realised today I had forgotten to adjust for the cows running slightly faster than the bad guys hence why they finished earlier. At the time of submission had not solved the reason for the issue and I tried adding more cows, but it magnified the issue.
Yes, it is near impossible to get a perfect score. It would take a lot more time fineness the distribution patterns.
My initial concept, I planned another shoot-out in a town with the remaining bad guys, followed by a boss shoot-out whose health would be based on the number of bad guys left.
I pondered whether to add cannon animation and recoil sound, but I was already over budget on development time.