Got the game today and am having a blast with it so far. Searching for all the puzzle pieces and kong letters while drooling over everything that's going on on-screen and David Wise's godlike soundtrack is pure bliss. I'm just a little perplexed about the alleged difficulty of the game. So far, I've beaten worlds 1-3 with all the collectibles (I'm saving the speedruns for after I beat everything a first time) and the challenge was completely adequate as far as I'm concerned. Sure, there were some spots that took me 10-15 tries (most of the time because of a hard-to-reach puzzle piece), but unless the difficulty curves very steeply soon, I'd say it's pretty much on par with DKCR (which, to be fair, is harder than your average platformer), with the exception of the mine cart and rocket barrel stages, which are a little more forgiving because you don't die instantly anymore.
Edit: Please do not take it upon yourselves to educate me about the rest of the game.
Edit: Please do not take it upon yourselves to educate me about the rest of the game.