The games controls are fine. Its the interface which isn't that great. Mainly that the game makes you press completely random buttons on maps (such as A, B, 1 or 2 at random depending on the object) and the Blob will ignore/disobey your commands often, causing you to get frustrated or die.
Not that you can't get around this, as many games (especially platformers) have those little 'tweaks' in their interface you learn to live with. But this game especially starts to get on your nerves. But unlike what many reviews keep saying, its not 'controls', its the user interface or commands.
As for the game itself, its fun, but pretty repetitive and not quite the 'revival of Mario 3 and Kirby' the game designers made it out to be. Its more like a game of trial and error with a set of limited resources. But that's just my opinion. I was really hyped for it, but it didn't meet my expectations. I ended up enjoying Muramasa and Little King's Story a lot more.
Six upcoming games you should look into:
Essay Pro