The object of the game is simple: As the music plays, circular notes will appear on the screen, and you must tap on them when converging circles overlap the notes. Occasionally, the game throws out "hold" notes that must be held down until they vanish, and "slide" notes that must be dragged into from outside of the note. Notes may also rotate, zoom, and scroll to where you must hit them; the result is what can be described as Osu! Tatakae! Ouendan with some elements of Camera Screw.
In addition to the initial Press/Start and Solarsphere episodes, several more have been added since the game's release:
- Darksphere and Darksphere/XXXL (2017) — paid DLC for Android, free for iOS
- Sun and Moon (2019) — paid DLC
- Empyral Bon Voyage (2019) — paid DLC
- Six Seconds Later (2020) — paid DLC
- Lights Go Round (2020) — paid DLC
In May 2020, Sta hosted a crowdfunding campaign to support continued development of the game as well as its sequel, Starbirth, which was formally announced in June 2021. It has raised over ¥2.4 million and met two of the funding goals; as a result the game got a new noteskin and the Lights Go Round DLC pack.
Tone Sphere provides examples of:
- Anti-Frustration Features:
- The timing windows on slide notes are looser.
- On iPhones and iPod Touches, the notes are slightly larger relative to the screen.
- Color-Coded for Your Convenience:
- The combo display that appears when you hit a note will flash purple on a Perfect, orange on a Great, and dark orange on a Way Off.
- When the note skin is set to "Rhythm", notes will be colored pink if they fall on a quarter beat, blue on an eighth beat, yellow on a sixteenth beat, and purple on a triple beat, while the "Dark" note skin additionally colors the note rims. If you're using the standard noteskin, note rhythms can still be differentiated by the shading of the rim.
- Damn You, Muscle Memory!: "otome" by suzutune also appears on another rhythm game, Cytus. Both games use ~2-minute cuts of songs, but the Tone Sphere cut and the Cytus cut vary, throwing off players who are used to one cut but not the other.
- Dynamic Difficulty: Inverted. The difficulty level for each chart is based off of the average star score for the chart. See Joke below to see what happens when a chart is made difficult to "fail" on.
- Easter Egg:
- Confirming chart selection with a quad-tap triggers autoplay mode, in which the game plays the chart for you. Getting to the results screen results in the performance comment "AUTOMATIC!"
- Entering "Sidesphere" as your ranking name triggers Side Sphere mode, in which the score and combo counters are turned 90 degrees, the idea being to turn your device in the same orientation.
- Entering "judgedelta" as your ranking name triggers judgedelta mode, which lets you adjust the timing windows to be harder or easier. Making the timing windows easier will disqualify your score.
- Everything's Better with Spinning: The camera likes to spin around on many charts.
- Gameplay Grading: On the surface, it looks like it's on a scale of 0 to 5 stars. However, earning 97.5% of the maximum "star score" will give you a 6th star. Earning stars raises your Sphere Level and unlocks new charts.
- Harder Than Hard: Above Hard difficulty is Expert difficulty, as well as the Spherical difficulty.
- Interface Screw: Some of the modifiers do this.
- Shakycam will cause the camera angle to tilt depending on your device's angle.
- Harlem Shake is similar to Shakycam, except the tilting happens uncontrollably and randomly.
- Stealth hides the notes, forcing you to rely on the converging circles to know where and when to hit notes.
- Pinhole shrinks the notes.
- Jumbo enlarges the notes.
- Sixth Sense Stealth hides both the notes AND the circles, forcing you to play the entire chart by memory.
- Cover is an inversion; it darkens the background, making it easier to see the notes.
- Joke Level: The "Spin Angular Momentum" charts. Both of them introduce exclusive "angle notes"; tapping a 45-degree note spins the camera 45 degrees, while tapping a 90-degree note turns the camera to another face of the chart. Both charts are also extremely trivial to clear, as only tap and hold notes contribute to the note count, but angle notes still add "star points", and if you put in even a little effort you will clear the chart; it's common to have all six stars before the song is even halfway done. Since the chart difficulty ratings are based on average player score, both charts also have a difficulty rating of zero.
- Licensed Game: A large majority of the tracks are licensed. However, Sta, a musician himself, also composes tracks that appear in the game.
- Nintendo Hard: The more difficult charts require heavy amounts of memorization to get decent scores on. Fortunately, the game comes with an autoplay feature.
- No Fair Cheating: Using the secret judgedelta modifier with an input higher than 1 (to make the timing windows looser) will disqualify the score you get with it.
- Non-Indicative Name: "2 Minutes Euphoria" is, in fact, closer to 3 minutes (2:47).
- Rank Inflation: Star rankings are out of 5, but getting a near-perfect "star score" will give you a hidden 6th star.
- Scoring Points: There are two scoring systems at work, further detailed here:
- The first one is the one shown at the top-left corner of the screen during gameplay and is used to determine rankings. There is a combo multiplier in place that maxes out at x4 at 12 combo. Silver notes add 10 combo, which can help you get back up on your feet more easily after a miss.
- The second influences your star ranking and clear status. Getting a Perfect is worth 2 points, a Great is worth 1 point, and anything else is worth 0. You need two stars out of 5 (obtained with 50% of the maximum star score) to clear the chart.
- Sound-Coded for Your Convenience: The hit sound effects. Different variations of the hit sound you're using will play if you get a Great or Way Off instead of a Perfect. Due to flaws in Android that would render syncing hit sounds and the on-screen action impossible, the Android version forgoes them in favor of vibrations.
- Unlockable Difficulty Levels:
- To unlock a track's Expert chart, you need to get 4★ or higher on the Hard chart.
- Some Spherical charts are only available on certain days of the week, or on April 1. Clearing the chart during its availability window will make it permanently available.
- Wingding Eyes: Weirs and Trin have unusual cross-shaped eyes. While it could be presumed that they're just closed, they're also seen "squinting" in some art. Made even more obvious by the fact that other characters have (relatively) normal eyes.