I enjoyed this game quite a lot, the increasing tension adds to the flavour. The player character is pleasantly fast. Eventually after I reached my goal of 100 deliveries I got too confident and was caught in a huge cluster of stupid humans.
I like that the humans need some time to attack is nice since you can avoid a sudden (second) death better and you can do risky dashes. Music is ok, some more sound effects would have been nice. I don't know if it's intended that you can run off-screen. Sometimes it's actually helpful, but you have to guess where you're at. A little indicator at the edge of the screen might help.
The biggest room for improvement IMO is in the level design. Well, the large free space is nice and somewhat necessary, but some more alleys or so might do for a greater variation.