That's a good little chopper shooter.
I liked the graphics, even though for some reason it was a bit too much for my laptop (maybe an optmization issue). I have noticed that the muzzle flash direction is weird, looks like it doesn't match the actual shooting direction.
The helicopter feels floaty, especially the landing part. Might be a part of the challenge but I'd prefer it to be more snappy and controllable.
As for features, maybe making it necessary to fully land (and perhaps stay for a bit) in order to pick up/deliver presents would add some challenge? Right now you need to be mid-air at a certain height which feels a bit off.
Some nitpicks aside, good job on the game!