• 35 new tracks
• 50 new objects
• 5 new tournaments
• 3 new achievements

It looks great!!

that game is so fucking hard... I have no fun with it anymore

" @DanGuy: Did you play it?   I'm curious, but also a little tentative about it it. I loved the first one up until I hit a wall in my progress. If it's got some more medium and hard tracks then I'm down, but if its more of those wacky side modes and impossible courses then I'd pass "

I played some of the DLC, it's great.  Still I didn't have much problem with the difficulty in the game, and even enjoyed beating the extreme difficulty levels.
 
Over 50% of the DLC content is probably around medium-level difficulty.  Only 2 of the new levels are in 'extreme'.  No new easy or beginner levels (which is good, because they'd probably be boring).
 
Only disappointing thing is the DLC doesn't seem to have that cool 8-bit song as featured in one of the trailers.

It's a great map pack. There is only 2 extreme tracks and they are not as hard as the others. And a lot of Medium maps and Hard maps.