App Overview

Percussions icon

Percussions

CRIMSON TECHNOLOGY, Inc · Music

"Percussions" is, as its name suggests, a new virtual musical instrument application which

$2.99 · In-app purchases

PRICE
$2.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
3.0
3 ratings · Below Average

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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A product spec, screen plans, and build steps for your coding agent.

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What's included17 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for Percussions: map the core Music workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Expand the library of instruments to include more varieties.

Assumption to check: Limited instrument selection compared to competitors.

Validate with people who use this workflow before building.

Hypothesis 2

Optimize audio loading and playback for smoother experiences.

Assumption to check: Performance issues when loading sounds.

Validate with people who use this workflow before building.

Hypothesis 3

Incorporate social sharing options to allow users to share their favorite sounds.

Assumption to check: Lack of social sharing features.

Validate with people who use this workflow before building.

Hypothesis 4

Redesign the UI to make it more modern and engaging.

Assumption to check: User interface feels dated.

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

"Percussions" is, as its name suggests, a new virtual musical instrument application which offers the performance of 18 kinds of percussion instruments in high sound quality. As well as actual percussion instruments, everyone can play each sound by various methods as follows: Tapping the screen, shaking the device, rolling the device, ... Moreover, favorite percussion instruments can be allocated to tabs in the tab bar and switched instantaneously. Also you can play percussion part of your favorite tunes with iPod music playback. A lot of unusual percussion instruments without seeing are included in this application. But those sounds might have been heard many times. Let's liven up your music party by the sound of this application. [Features] -Including 18 percussion instruments Agogo, Bell Tree, Bongo, Castanet, Claves, Conga, Cowbell, Cuica, Guiro, Maracas, Matraca, Scratch (Turn Table), Shaker, Tambourine, Timbales, Triangle, Vibraslap, Wood Block -Various perform methods in answer to actual instrument Tapping the screen: Bongo, Castanet, etc. Rubbing the screen: Guiro, Cuica, Scratch, Matraca, etc. Pressing down the screen (for playing muted sound): Conga (High), Triangle, etc. Swinging the device downward: Cowbell, Timbales, etc. Shaking the device: Shaker, Maracas, etc. -Low latency and real output sound by internal software synthesizer Reverb effect Note; Please set animation off on the setting view when feeling that the response is not quick because of the model etc.

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Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

SUGGESTED BUILD STACK
React Native
Expo
expo-av
react-navigation
zustand
BUILD KIT DIFFICULTY
Intermediate

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.