HarmoKnight bills itself as a “rhythm platformer,” and the basic nuts and bolts behave as such. Protagonist Tempo is on a quest to deliver a magic note staff to Symphony City while harnessing the powers of friendship in ways only the finest Japanese children's parables can deliver, and there's no slowing him down, thematically or literally. He trots across the screen automatically, but you can make him jump or take a swing with his musical staff on command, and nearly all of the game's action derives from these two basic functions. Enemies clearly telegraph when you're supposed to hit them by chiming and pulsing to their particular rhythmic wrinkle, be it syncopation, triplets or whatever else, long before they reach Tempo. Nearly all enemies can be felled with a solid whack or two to the beat of the background music, and getting that timing just right lets loose a super satisfying thwap. Fireballs, spiky boulders and other inanimate fare that impedes your journey must typically be jumped over, and some tightly placed spikes and other deadly configurations make sure you're really jumping to the beat and not cheesing the whole premise too much. The controls generally feel good, if a little lax in their forgiveness toward button presses that are probably a little too late to have counted.

HarmoKnight also contains a number of boss and surprise attack levels that put a more cinematic, QTE-infused taxation on your timing. The game's announcer will yell out your instructions to the intended rhythm beforehand - “Left, Right, Hit-Hit-Hit!” to dodge a few falling boulders and then smack some encroaching monsters, for example - and then it's up to you to repeat that line back, Simon Says-style, and fulfill the rhythmic prophecy. Along with the game's simple, bold graphical flair, these segments reminded me a little of Sega's Space Channel 5. No mean feat. Tempo meets a few other characters on his quest, and they occasionally tag into levels to offer their own slight variations on the action. One such traveler has a pet monkey, and they each place their own cursor on the screen, requiring you to command two buttons and rhythmic hot spots at once. Having further, more minor shakeups to your input is a good idea in theory, but its implementation is sloppy here. When Tempo tags out an ally or vice versa, there's no effort made to continue the music seamlessly. Instead, the audio – and any semblance of groove you had going – grind completely to a halt, at which point the game seems to briefly load before continuing with the new character. It's really jarring, to the point where the game would have been better off without those particular change-ups.

The number of ways the game tackles rhythmic platforming is commendable, and its all contained within a beautiful wrapper, but HarmoKnight botches a few key elements critical to rhythm games in ways that end up damaging the big picture. It's all too breezy, for starters. Earning Gold flowers – the highest standard of performance – feels too easily accomplished, and although they each unlock a faster version of their respective level, it's a hollow extension of content that isn't exciting to go back to. That's largely due to the game's soundtrack, which I haven't even mentioned until now. Sadly, that's because there just isn't a lot to say about it. The game is full of happy little tunes that rise and fall on major scales, cascading around until a level's conclusion. It doesn't sound bad, but it's completely without interest. There's nothing to pick out and hold on to, no melodies to keep. Once you reach the final few worlds, you'll already have the distinct impression that the experience is beginning to run thin. Try and replay it past its brief initial run time, and the excitement plummets.

It really is the fatal flaw keeping HarmoKnight from its place as a great. The presentational pieces are there, and the controls tight, but when it comes to delivering a memorable set of tracks to underscore both the thematic and mechanical elements of the adventure, it doesn't dig near deep enough. Without the joy of music to which the most successful games in the genre are conduits for, a lot of the effort and talent behind this charming game winds up feeling a little hollow.