The object of each stage is to completely fill your note meter at the bottom of the screen until you can see five full note icons. Once this occurs, the screen will flash, and you will immediately exit the stage from wherever you are, and initiate a boss battle. To collect notes, you must fire your bubble beam at note bubbles. For each note bubble that you collect, your note meter will fill up according to how many notes were on the bubble. In the event that you complete the stage before you fill up your meter, the stage will loop to the very beginning again, only this time any note bubble that you already collected will be replaced by an enemy. The stage will loop indefinitely until you manage to fill your meter. The longer it takes, the harder it becomes, since more and more note bubbles will be replaced by enemies as you collect them. It is not uncommon to have to loop through a stage once, but you should avoid the need to loop through it two or more times. Take a mental note of the bubbles you missed and be sure to collect them on the second pass through the stage.
Boss battles are conducted on a single screen. Otocky must fight against a giant note, or some other musical symbol. The note or symbol will have holes in it. You must fire you bubbles into these holes. Every time you successfully hit a hole, your note meter will decrease. The boss will be defeated when you fully deplete your note meter. The boss will move left and right, or it will move up and down. On occasion, 4 enemies will spawn from one of the nearest holes, and spiral outward. While your special B button weapon is useless against the boss, it can still be used against the spawned enemies. In later levels, the number of spawned enemies will increase to 8. Other than the number of enemies which appear, and the shape of the symbol in question, all boss fights are identical, from the first stage to the last.
|Stage 1 - Otocky Land
||Stage 2 - Onpu Circus|
|Otocky Land is, quite naturally, the easiest stage. It eases you into the game by making plenty of note bubbles immediately available (meaning you don't have to pop too many of them out of note blocks) and at a slow even pace. Even if you have to loop back around and repeat the stage, the enemies are usually motionless and easy to avoid or defeat. This is the only stage to feature music which changes based on how many notes you have collected.
||Onpu Circus is still a fairly easy stage, but it spaces the notes out a little farther apart, so you may have to move around more to collect them. The notes also move around the screen a little faster, so your reactions must be faster to. You will be introduced to the fast bubble, the recording bubble, and the stop bubble if you dislodge them from their hiding places.
|Stage 3 - Beat Block
||Stage 4 - M.B Percussion|
|Enemies will start becoming a little more aggressive on this stage, but they are still easily avoided if you can predict their path. More notes are hidden inside of note blocks, so you must be ready to fire quickly. You must fire twice to collect a note bubble from a note block; once to dislodge it, and again to collect it. Most of the bubble on this stage will travel up or down from their blocks.
||There are no free appearing note bubbles on this stage. In order to collect notes, you must dislodge them from the note blocks that appear on top of what appear to be the surfaces of electronic drums. Sometimes an enemy will squat over a valuable note block, so you must remove it first. Other times, and enemy will actually jump out of the note block you destroyed, so be careful.
|Stage 5 - Soundscape
||Stage 6 - Glass Waltz|
|You will travel quite far into the start of this stage before you see a single note bubble. As a result, a majority of the note bubbles can be found in the later half of the stage, especially inside sets of note blocks. Of special importance is the triple note bubble found near the very end of the stage, surrounded by a set of enemies. Don't let it get away.
||The good news about this stage is that there are no note blocks; everything that you can collect is freely available throughout the stage. What's more, a majority of the notes (and some of the enemies) are traped inside bubble containers which limit their range of motion, making it easier for you to capture. Don't expect this stage to be easy, but it's a little easier than some of the previous stages.
|Stage 7 - Music Plant
||Stage 8 - Onple Trip|
|This stage contains a large number of enemies. If you are not careful about where you are sitting while you fire your bubble beam, you may be in for a rude awakening as you collide with several enemies that move across the screen very quickly. This is one stage where you want to focus more avoiding enemies, and save collecting notes for when it is safe to do so. It is best to avoid hanging out too much in the center of the screen. Try staying more to the right.
||The Onple Trip is another stage where a majority of the notes you need to collect will be contained in note blocks. There are also a large number of enemies in this stage, but their placement is a little more forgiving than the previous stage, so you should get hit by surprise as often. Relying on diagonal shots can be very useful at this point. It allows you to hit blocks in a safer manner in case an enemy pops out.
|Stage 9 - Onpu Factory
||Stage 10 - Cubic Keyboard|
|Don't let the fact that a majority of the note bubbles that you need to collect are contained make you believe that this stage is easy. The paths that the enemies take are set up to intentionally interfere with your note collection efforts. You will want to collect an A bubble as quickly as possible in this stage so that you can attack from farther away. Some of the machinery throughout the stage can hurt you, but it can also be destroyed.
||Even if you've become accustomed to collecting note bubbles from note blocks, this stage will be a challenge. The way that many of the bubbles escape from the blocks takes them just out of the line of your fire if you're used to firing straight up or down. You will have a little more success firing at them diagonally. As usual, be mindful about the placement and motion of the enemies so that you don't lose too much of your meter getting hit.
|Stage 11 - Final Notes|
|In many respects, the features of this stage are invisible. As you fire in different directions, different notes light up in the background. These notes will be your only clues as the the whereabouts of the note bubbles that you need to collect to advance to the last boss. When you begin the stage, you won't find any note bubbles for a long time. You will fight a string of enemies while three item bubbles pass by. First you will see an A bubble, then a B bubble, and finally a REC bubble. After the record bubble passes you by, you will then be able to dislodge note bubbles from their invisible hiding places, usually associated with the placement of the notes in the background. You will certainly want to catch that first A bubble to extend the range of your bubble beam. The safest place to remain throughout the stage is roughly a third of the way down from the top of the screen while you fire down continuously. It will take some practice to find the right location, but after you collect two A bubbles you should be able to fire across the entire bottom of the screen.