ノスタルジア's machine serial number and version ID start with PAN.
According to sound director wac, ノスタルジア is meant to be both a "piano game for those who do not play piano" and "a BEMANI game for those who do not play BEMANI".
ノスタルジア runs on a modified BeatStream cabinet, although a dedicated cabinet (which lacks the upper screen) is available as well. The piano design of the cabinet changed several times during the location tests, although the piano design on the final cabinet resemble to that of the first location test (white and black keys, but only the white keys are used for gameplay). ノスタルジア is keysounded, but "extra" sounds do not play if there are no notes present.
- ノスタルジア (released on March 1st, 2017)
- ƒORTE (released on July 19th, 2017)
- ノスタルジア Op.2 (released on September 26th, 2018, Current Version)
Two game modes are available at the start of your credit:
- STANDARD mode: Can be played with either regular credits or PASELI. This is the regular play mode, Normal and Hard charts are available, while Expert charts can be unlocked by clearing Hard charts with an A grade or higher. Real charts can be purchased with the in-game currency nos.
- ƒORTE mode: Requires PASELI (Japanese version). Expert and Real charts are available by default, and items in-game can be obtained more easily. In the Korean version, this mode requires twice the credits of STANDARD mode. This mode is not available in the Asian versions.
Much like the KEYBOARDMANIA series (or even more similar to Rayark's Deemo, VOEZ, and SEGA's CHUNITHM), players have to hit a piano key while the scrolling down notes reach the judgement line, located on the lower screen. However, players do not have to hit the specific key on the piano to match the note on the screen. Instead, hitting the key(s) surrounding the scrolling note is sufficient. On higher difficulties, fewer surrounding keys count toward a correct note "hit". Hits can be judged as ◆JUST, JUST, GOOD, NEAR (introduced in ƒORTE), or MISS.
Three difficulties (Normal, Hard, and Expert) are offered for each song, although in the JAEPO 2016 location test, each song had only one difficulty. A fourth difficulty, Real, was added in ノスタルジア Op.2.
Notes with a red hue are meant to be hit with the right hand, while notes with a blue hue are meant to be hit with the left hand. Certain songs will "suggest" that players cross their hands over.
Besides the basic notes, there are three types of special notes:
- Tenuto: A long note, much like hold notes on other BEMANI games.
- Glissando: A slide note across several keys (not present in some Real charts).
- Trill: Similar in appearance to a tenuto note, it has to be hit with two adjacent keys on a quick sucession.
Gameplay options include Notes Speed (from 1.0 to 3.0, with 0.1 increments), Headphone Volume, Judge Timing (introduced in ƒORTE, allows players to adjust timing from -5 (early) to +5 (late)), and Judge "NEAR" (introduced in ƒORTE, toggles ON/OFF the NEAR judgment). These options can be adjusted once a song is selected (but before playing it). Also, a metronome option (named GUIDE) can be toggled ON/OFF during the song and difficulty selection screens, and can be turned on/off during gameplay by touching the metronome icon.
The ability to lift or lower the judgement line (including the on-screen piano guide area) was added in the March 22nd, 2017 update.
The game does not feature a life meter. Instead, similar to the jubeat series, a minimum score of 700000 points is required to pass a song. Failing a song does not automatically net a game over, regardless of the mode you have chosen.
When the song is finished, the player will receive a score up to 1000000 depending on his/her performance, and will receive a message depending on whether the song was cleared with Perfect Performance (full combo with 1000000 points), Full Combo, It's Fantastic (regular clear), or Finish (fail).
Let N = Note count
Let J = ◆JUST count
Let j = JUST count
Let G = GOOD count
Judgement point = 1000000(J+0.7j+0.5G)/N
NEAR (introduced in ノスタルジア ƒORTE) and MISS give 0 points.
Ratings will also be assigned based on the score:
|S||950000 - 999999|
|A+||900000 - 949999|
|A||850000 - 899999|
|B+||800000 - 849999|
|B||750000 - 799999|
|C||700000 - 749999|
|-||0 - 699999|