You're right. I tried it, but was in too much of a hurry to give a proper review.
Today I have some more time, so here goes.
Let's start positive:
The menus are excellent! Very easy and clear to move through, looking really flashy and fits the style of the sledge race completely. They got the cartoonish look just right.
The background of the main menu is worth mentioning. You've done it spot on! Not distracting, yet you kept me from getting bored.
Music is also very good, again, fits the style nicely.
Next is the in-game HUD. I like it a lot. Just as before, looking organized yet flashy. The text which appears as the race ends is done nicely as well.
One thing, you've forgotten to add a mouse pointer. It's now impossible to play this game in full-screen.
And, this might be unnecessary, you should add a custom loading screen.
Also, the physics bugged quite a bit. I got stuck to one of my opponents almost immediately.
I assume you won't like hearing this, but to be honest, I didn't like the actual gameplay very much. I was expecting to see a funny down-a-slope kind of race, so I was disappointed to see it was on a horizontal course. I would really recommend this slope kind of race. Create a mountain side with a down hill ski slope with some low-poly, cartoonlike trees and snowmen which you have to evade. You could even consider pick-ups.
And finally, I would suggest keeping the entire upgrade thingy simple. Personally, I would make it money based. The player could earn money for each race, getting more money for harder levels and for ending with a higher position. Then, the player can buy new parts for his sledge and browse through the already bough items. Better items would be considerably more expensive. A level system wouldn't be necessary.
Combining the getting of new sledge parts and the gaining of skillpoints which you can spend on skills is too much of the same. I would drop it.
On the whole, you got a very nice looking game and you should of course build it as you please.
You're on the right track, keep this up.