The game uses the traditional "falling notes" style of gameplay. Notes scroll down the gameplay lanes and for each note, the player must hit the corresponding part of the "Ground Slider" controller. Tap notes require the note to simply be tapped, Hold notes require holding down the necessary part of the slider until the note ends, Slide notes are similar to Hold notes but the player must drag horizontally along the slider, and Flick notes require the player to slide across the part of the slider corresponding to the note.
However, there's a unique twist to this formula: In addition to all of these, there are also Air notes, where the player must physically lift their hands off of the slider and wave them through a sensor above the slider; some Air notes simply require the player to tap the note and then lift their hand off into the sensor range, others require the player to keep their hand in the air afterwards to hit the mid-air "Air-Action" notes, and some other Air notes have the player move their hands down through the sensor to hit notes on the slider.
Notes need not be fixed-width like in many other rhythm games; each note can be as little as 1/16th as wide as the playing field, or as wide as the entire playfield, so depending on the note you have some leeway in how precise you have to be to hit it.
It is currently one of the most popular rhythm games in Japan, having surpassed DanceDanceRevolution in commercial success there and often competing with beatmania IIDX on that same metric, despite Sega only having about half as much time in the arcade rhythm game scene as Konami. It was originally a Japan-only game, but high demand outside of Japan led to SEGA producing a separate line of releases for the Asia Pacific / Oceania region.
Compare Deemo, which shares a few common interface elements such as the variable-width notes, Arcaea which borrows the "air notes" concept, Nostalgia (BEMANI) which some have described as "Chunithm except with piano music", BanG Dream! Girls Band Party! which has been called "Chunithm but with idol bands" by some players, Tokyo 7th Sisters and Project SEKAI, both of which effectively port Chunithm mechanics onto the mobile screen (since the November 2017 update for the former), and Dance Rush which has been described as Chunithm EXCEPT WITH YOUR FEET!
Games in the series:Japanese releases
- CHUNITHM (2015)
- CHUNITHM PLUS (2016)
- CHUNITHM AIR (2016)
- CHUNITHM AIR PLUS (2017)
- CHUNITHM STAR (2017)
- CHUNITHM STAR PLUS (2018)
- CHUNITHM AMAZON (2018)
- CHUNITHM AMAZON PLUS (2019)
- CHUNITHM CRYSTAL (2019)
- CHUNITHM CRYSTAL PLUS (2020)
- CHUNITHM PARADISE (2021)
- CHUNITHM PARADISE LOST (2021) — current version
Asia/Oceania Pacific releases
- CHUNITHM SUPER STAR (2020) — current overseas versionnote
The CHUNITHM series provides examples of the following:
- All or Nothing: ExTap, Slides, and Flick notes can only be rated Justice Critical or Miss, skipping Attack and Justice entirely. Downplayed, in that this is because the Justice Critical window overrides the Attack and Justice windows; so long as you hit them at all, you'll get a JC.
- Bullet Hell: Some World's End charts have the player holding one long note throughout the entire chart and trying to dodge damage notes on the track.
- Call a Hit Point a "Smeerp": The highest three judge ranks: Justice Critical (perfect), Justice (great), and Attack (good). Only the Miss judgement is Exactly What It Says on the Tin.
- Color-Coded for Your Convenience: Tap notes are pink, ExTap notes are glowing yellow, Hold notes have yellow tips and yellow-and-purple fills, Slide notes have blue tips with purple-and-cyan fills, Flick notes are blue, upward Air notes have green arrows, Air-Action notes are hot pink, and downward Air notes have pink arrows. During certain WORLD'S END charts, Damage notes are purple.
- Flawless Victory: Clearing a chart with only Justice or Justice Critical judgements results in a congratulatory "ALL JUSTICE!" message. The usual "Full Combo" is here, as well, if you get at least one Attack.
- Gimmick Level: The WORLD'S END charts. In place of a difficulty number, each of these charts has a kanji corresponding to the type of gimmick it uses.Examples include...
- Harder Than Hard: The difficulties go Basic, Advanced, Expert, and Master.
- Lighter and Softer: Whereas the original game and its PLUS version primarily use black and gold as its dominant colors, CHUNITHM AIR and its respective PLUS version use a sky theme with lots of turquoise and purple.
- Non-Standard Game Over: Skills classified as "Absolute" will end the song prematurely upon meeting a specific condition, usually getting too many Misses, Attacks, or non-Critical Justices.
- Portmanteau: The title is one on the words "chuunibyou" and "rhythm", or "tune" and "rhythm". This was confirmed in an interview by Japanese game publication 4Gamer
- Rank Inflation:
- The ranks go D, C, B, BB, BBB, A, AA, AAA, S, SS, SSS.
- Scores seem to be out of 1 million points, however, it is possible to go slightly over a million, and in fact, you need a little more than 1 million (1,007,500) for an SSS. This is because while a Justice gives 100% of the "maximum" note score, a Justice Critical gives you 101%.note
Just to emphasize the inflation, the Justice Critical judgement isn't even particularly hard to get by arcade rhythm game standards, as the timing window for it is ±33 milliseconds, the same as "perfect" judgements in many other rhythm games.To compare A 95% score in most other rhythm games means the player did well, while here, 950,000 is actually considered only an average score.
- Required Spinoff Crossover: Several songs from maimai and O.N.G.E.K.I. make their appearance here, and in return, songs from CHUNITHM cross over there.
- Scoring Points: Scoring is based strictly on accuracy. Getting a Justice gets you 100% of the note score, getting a Justice Critical gets you 101%, Attack gets you 50%, and a Miss gets you nothing. Hold and Slide notes are each counted as multiple notes. The score is based around 1,000,000 being a 100% score, with 1,010,000 as the actual maximum score obtainable.
- Some Dexterity Required: Some patterns involving Hold or Slide notes are best done by crossing your arms.
- Subverted: you don't have cross your arms, you can bring your hands together and then move them apart and it'll still count. Double subverted if one hand is dealing with Hold/Slide notes and the other is dealing with Air-Action notes.
- Too Long; Didn't Dub: SUPER STAR is mostly translated into English, however Character Skill descriptions either only have partial translations alongside the original Japanese text, while other Skills' descriptions have no translation at all.
- Unwinnable by Design: You need to fill the gauge a certain number of times in order to clear the song, and the number of gauges you need to fill depends on the map among other conditions. It can happen that you are unable to fill enough gauges to clear the song, even if you get a perfect score; you also need the right Characters and Skills to be able to meet certain clear conditions. That said, Death Is a Slap on the Wrist; clear/fail only matters for map progression and unless you are playing in course mode, you will always get a full set of stages even if you fail all of them.