Shooting up or down-hill adds another dimension, so to speak.
Yes, but this freeper won’t need to consider it at this point.
Angles, either up or down shorten the actual ballistic distance, so one would hit high either way. But, for example, the quick solution is distance to target times the sine of the angle from horizontal. So, even a 30’ slope word result in a range decrease of .988, 1000 yds becomes 988 yds, 12 yards short..... Well within minute of deer