@Wagram The game isn't that hard but I think part of the mentality is that DKC really scolds stupid mistakes. Couple that with a player base that probably hasn't played too many 2D platformers recently and you can see why they think it's so hard. Also the bonus stages, though a bit monotonous after a while, are fun the first few times around.
@Kenology I like that this game gives you the freedom to get puzzle pieces and KONG pieces at your own discretion. I probably would still be in World 2 or 3 if I was trying to get all the puzzle pieces but getting KONG at the end of a level is satsifying to me. Doesn't mean I haven't gotten all the pieces in a few levels though
@Gojimaster I haven't played the co-op too much but pretty much anyone can play. It's pretty NSMBWii-esque in a drop in and out and be a barrel instead of a bubble kind of way. It pretty much requires teamwork as only Donkey Kong can pound on stuff and Diddy Kong is much speedier and has the pop-gun and barrel rockets. Though you can play co-op with Diddy Kong on Donkey Kong's back which helps conserve lives or deplete them, depending on the Donkey Kong player's skill.
Pixel Art can be fun.