I don't even know where to begin with this one!
The map design is awesome - gradually opening up additional paths between the two mailboxes made each section feel memorable. The map never grows, yet you constantly feel like you are exploring and building a relationship with particular jumps and platforms as you optimize your route.
The player movement feels pretty good and I was blown away by the love and care you put into the tiny animations. There were so many little details - dust clouds underfoot, subtle bobbing while in motion, fluttering scarf, etc
As a mediocre platform player, this was HARD. I only managed to deliver 3 packages. But the game is never discouraging - the first delivery without any penalty allowed me to learn the route at my own pace, so I felt more and more confident on each subsequent playthrough.
Some of the penalties felt a little more punishing than others, but none of them were unfun. They all added something to the gameplay, rather than taking away or limiting my ability to platform.