I really, really liked the SMB2 version USA and Europe got. Like many have said, it was really a breathe of fresh air in terms of gameplay and settings. This was really welcome back at the day, since basically every kid had played tens of hours of SMB.
In my opinion, the graphic design of SMB2 is also the most cohesive in the series (well, YI builds nicely around the gimmick of crayons, but not too memorable) and the enemies are among most memorable ever brought to the Super Mario universe. Just think of
- Shy-Guys
- Pokey - the big cactus thingy
- Bomb-ombs
- Sniffits - the shooting gasmask enemy
- Phantos - the face that chases you when you get a key
- Cobrat - the snake in the pot
- Sparky - the electic shock monster going around platforms
- Mouser - the bomb-throwing mouse
- Tryclyde - the snake with three heads
- Wart
For images and descriptions of the enemies, see
http://www.x-entertainment.com/articles/0718/