The first game was great, lots of content to it, and even a charming special room for collecting all 10 dragon coins, which in turn would grant you awesome abilities such as the super powerful level 3 fire and infinite flight. And then there was the purple 'mirage door', which would make water seem like air.
Compared to it, this game seems just a bit... underwhelming. There is twice as few content, the mirage door has been replaced by a 'freeze pear' which does less than the last game's special thing did. And the dragon coins don't give you a special room of some kind, and the abilities you gain from it aren't as awesome. Your flames go just a little bit further (a third flame would have been awesome!), you're invincible a bit longer after hits, and you have a third wing flap. All just minor things that don't make feel like one epic dragon. ;P And collecting extra hearts and powers inside of levels just feels more rewarding than buying them with gems that you'll never have a shortage of.
All in all, while the other game had much more charm in all the places, this was a pretty good game while it lasted too. Expecting 8 full worlds in the next game! :P