Jr's Revenge!
The levels are littered with birds, sparks and little choppy-things, all of which have obviously been payed-off by Mario to take out Jr. Similar to the original, you have the ability to jump over things, but you now you can climb on hanging vines, which you usually have to jump up to grab.
After all these years, the levels can still be a slight challenge and still hold replayability. No, you aren't going to sit down and play Donkey Kong Jr for 5 hours solid, but for 15 minutes you can look back at history and smile.