An enjoyable platforming game. I enjoyed working my way through each level. Discovering the secret elements (a hidden star, an alternate exit, or just a shortcut to completing the level) are some of the best parts. A bit embarrassed I was beating level 31 randomly without seeing why until later. I like the fact that the harder modes change aspects of some of the levels. I like that a level select is included (to be able to practice particular levels) and that the Gallery has plenty of stats.
The one aspect of the game I'm not fond of is the way it handles moving platforms. I'm not sure if I'm using the correct terminology but my dislike is that they have separate momentum than the player. This means that, for horizontal moving platforms, you have to move to stay on the platform. For vertical moving platforms, this means that if you try jumping at the very top it can stunt your jump. It's not bad for the most part as it's something you just have to adjust to, but it can be a real kick to the groin at level 38 on hard mode ('A true platformer' indeed; now if I can only find some consistency only level 43 will stand in my way).
A couple of minor bugs that happen infrequently but just want to mention: lvl 23 (hard mode) one of the smiley faces pushed the feather off of the screen (or maybe this is supposed to happen?); lvl 19 a couple of times when I ran to the feather I wound up pushing it off the ledge (and onto the spikes) instead of collecting it.