Let me just start by telling you that G.I.F.T. is a very fun game! It was challenging, the gameplay was smooth, and I was very engaged. Having told you that, I'd like to provide some feedback for you because I really want to see this game reach its full potential.
First off, the graphics could use some work. While I enjoyed the overall retro look of the graphics, I feel that the level tiles and snowballs didn't quite fit in. More importantly, why is the kid just sliding? Why not make him skate across the ice? If you're seriously interested in getting some better graphics into this game, please contact me. I've pushed a few pixels in my past and I'm sure I could make some time to give you a hand.
Next, let's talk transitions. Proceeding from the title screen to the first level, and then from each level to the next, is kind of boring. You are essentially "dropped" into each level without even a congratulations for completing the previous. I suggest at least displaying a cool intro to each level, even if it's just the words "Level (insert level number here)" displayed in big letters. It would also help to prompt the player to begin the level before proceeding from each intro. At the end of the level, the box could run away from the player to the next level. This would make sense because you technically don't actually open the box until the end of the game (more on that in a moment).
Next, beginning with Level 9, the games difficulty increases sharply. I mention Level 9 specifically because I found myself having to "cheat" to complete it. I had to change my direction right before I got to the edge of the first platform so I would drop down to the platform directly below me. It's wise to avoid creating levels based on a flaw in your gameplay mechanics, especially without giving the player a heads up. You also used this same flaw to design the last level. I suggest fixing this flaw and then considering how each level can be designed to stay within the intended bounds of how the game is played. You've got the right idea in the first few levels, which were pretty fun!
Finally, the ending was somewhat of a disappointment. I still have no idea what was in that box! Also, you're English could use a little bit of work (the ending text was a little hard to understand). Again, if you'd like some assistance, contact me and I'll help you out.
There you go! Make a few tweaks here and there, revamp your graphics, and design some new awesome levels. Like I said, I really want to see where this game goes and I hope you take my tips into consideration.