This is a moderately fun game, but there's a lot that needs refining. For the good points, the music is pretty nice and diverse, as well as the nice bonus shop items. The game gets slightly easier after practicing, and it's always satisfying to jump into a huddle of coins.
However, there are many flaws. I know the game is based around a one-button concept, but the ENTIRE game doesn't have to be restricted to it. The shop, for example, should be accessible with menu keys (as well as able to be seen with all items), not just a single, random shop item (that usually costs way too much).
The game can also put you into unwinnable and hopeless situations that you cannot avoid, leading to a inevitable and unstoppable death. This is a little cheap, and it sucks when it happens. The one-button concept is nice at first, but when you can't change directions or jump more times, it gets disheartening.
Also, the game should save your costume/music/palette settings. Having to change them manually every time to your liking is a waste of time. There should also be a quick-restart button, like an instant restart. Having to accept through all the options to play again is pointless, and as I mentioned before, if you had a save setting for your preferences, you wouldn't have to skip through everything. If you had a normal menu scheme, a player could manually change their preferences when they want to. Again, the whole game does not have to be restricted to one button. It feels lazy, when it comes down to it.
Also, to get items in the shop requires too much grinding. You don't get many coins, and because the game periodically screws you over by giving you too few options of control of your character, you will die before you get a decent amount of coins.
There's a lot wrong with this game, but if the previously mentioned problems are fixed, this would be an amazingly fun game. More control over your character, more coins placed around the map, more leniency in map awareness, ability to save your settings/preferences, options menu, and a fully browsable shop would be great and outlandishly needed additions to this game.