The player plays as an alarm clock who must wake up the mechanical pidgeon in an old man's cuckoo clock at the right time. Each night, the pidgeon requests a specific time for the player to wake up. A beat is then counted off, and the clock starts ticking from 1 o'clock. After roughly four beats, the screen fades out, requiring the player to count on their own. When the needed time is reached, the player must stop the clock. The pidgeon then wakes up and checks the time.
This gets mixed up in various ways as the game progresses: sometimes the pidgeon requests a time off the hour, and later on the music may cut out entirely. Sometimes, the music is played in swing rhythm, as well.
Perfect!/Ace!?: The time shown is the exact time the pidgeon requested. The pidgeon then pops out of the cuckoo clock and toss a bean into a flower pot, which blooms into a petaled flower, and a point is counted. The old man smiles. The game continues to the next night.
Early!/Late!?: The time shown is slightly off, causing the clock to adjust to the exact time, hiding the mistake. The pidgeon pops out and tosses a bean like normal, but the resulting flower has no petals, though a point is still counted. The old man becomes embarrassed. The game continues to the next night.
Miss...?: The time shown is completely off. The pidgeon is shocked from waking up too early or oversleeping. If the player does nothing, time flies and eventually night falls, with the pidgeon missing a day. Either way, the game is over.
If the player is successful, the pidgeon pops out and tosses a bean into a flower pot, where a flower blooms. Occassionally, the beans are rainbow colored, which bloom into flowers with rainbow petals. Sometimes, the flowers bloom into Hair Vegetables instead, shocking the old man.
While none of the characters are named in-game, internal comments refer to the pidgeon as Hato-kun (ハト君?, Pidgeon-kun)[1], the clock as Mezamashi-kun (めざまし君?, Alarm Clock-kun)[2], and the beans as Omame-chan (おまめちゃん?, Bean-chan)[3].
Inputting the code word CLOCKWORK in Police Call gives the player a tip about there being a code word in this game (the word is BOUTS: every so often the flowers bloom with a letter on them, spelling it out). The code word can be put into Police Call for an easter egg.
Various characters from Rhythm Tengoku sometimes make cameos during the nightfall scene. Examples include: