Comparison

Phosphor Emulator vs Keep The Fly

Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.

Head to head
About

Phosphor Emulator

This app provides a premium emulation experience for Game Boy, Game Boy Color, and Game Boy Advance games on modern iOS devices. It features advanced controls, instant save states, and unique functionalities like rewinding gameplay and AI play.

Highlights
  • Rewind and fast-forward gameplay
  • Instant save and load states
  • Customizable touch controls
  • MFi controller support
  • Game Boy Camera and Printer integration
  • AI Play feature
Features
Read full description

Phosphor is a free retro game emulator for iPhone, iPad, Mac, and Apple Watch. Play Game Boy, Game Boy Color, and Game Boy Advance games, plus Nintendo DS games on iPhone and iPad, with save states, fast-forward, rewind, iCloud save sync, controller support, and community mods. No ads. No subscriptions. No accounts. No tracking. Import your own compatible ROM files through Files, iCloud Drive, or AirDrop. Organize your library, pick your controls, and take your favorite handheld games anywhere. WHY PHOSPHOR? Phosphor is designed to feel like a handheld console. Deep black screen wells, glowing CRT effects, responsive controls, and color themes bring classic games to modern Apple hardware. Play in portrait or landscape, adjust your speed with a scrolling dial, and return quickly to your last session. NINTENDO DS ON IPHONE AND IPAD Import compatible .nds files and choose single-screen or dual-screen play. Start with a focused single-screen layout, switch to both screens from the menu, and swap screens when you need to. Touch-screen input, microphone controls, and portrait and landscape layouts keep DS play flexible. MODS POWERED BY GEN1RECOMP Supported games can use the integrated gen1recomp engine to run compatible community mods inside Phosphor. Keep your library, controls, and display framing while exploring new ways to play. The updated engine brings gameplay and compatibility fixes. Features vary by game, engine, and mod. Rewind and cheat codes are available with Phosphor’s standard emulator core, not during gen1recomp play. FEATURES Classic handheld games Play compatible .gb, .gbc, and .gba ROMs, with .nds support on iPhone and iPad. Import individual games or supported ZIP archives and search your library. Link Cable trading Connect supported games over the same Wi-Fi network. Gen 3 Pokémon Link Cable support covers Ruby, Sapphire, Emerald, FireRed, and LeafGreen. Compatible games, in-game progress, and normal trading restrictions apply. Fast-forward up to 15× Choose 1×, 2×, 3×, 5×, 10×, or 15× where supported to move through battles, travel, and repeated sections. Available speeds depend on the game, core, and device. Live rewind Hold rewind to return to an earlier moment and try again with the standard emulator core. Save states and quick resume Create quick saves and save-state slots, then return to your session with quick resume where supported. iCloud saves Sync compatible in-game saves, quick saves, and save-state slots across devices using the same Apple ID. Check for saved progress in Settings and choose which copy to keep when saves conflict. Game files are not backed up; after reinstalling, reimport them with their original filenames to reconnect your saves. CRT display and themes Customize your screen with scanlines, phosphor glow, dot-grid texture, vignette, contrast, and color themes. External controllers Play with compatible controllers or use responsive touch controls, haptics, and layouts designed for portrait and landscape. Cheat codes Use supported cheat formats with compatible games on Phosphor’s standard emulator core. Apple Watch play Take supported games to your wrist. Platform and feature availability vary by device; Nintendo DS play is available on iPhone and iPad. Live Activities See your current game, play time, and quick-resume status from the Lock Screen. BRING YOUR OWN GAMES Phosphor does not include games or ROMs. Provide your own legally obtained, compatible game files. Community mods have their own authors, licenses, and compatibility requirements. Save states and other features may vary between emulator cores, engine versions, and devices. A classic handheld feel. Modern Apple features. Your games, your library, your way to play.

About

Keep The Fly

Features
Read full description

Keep The Fly is a small retro arcade game about keeping one tiny fly alive for as long as you can. Tap to move, dodge what gets in your way, and try to stay calm when the gaps get tighter. Each run is short, a little chaotic, and easy to restart, which makes going for a better score feel natural. Play for your own best score, or sign in to place your result on the leaderboards. If you enable location, you can also compare your score with players from your country or nearby area. Simple idea. Quick runs. One stubborn fly.

Screenshots

Phosphor Emulator4 screens
Keep The Fly4 screens

Verdict

The call

The clearest difference is ads: Phosphor Emulator at none against Keep The Fly's shown. Phosphor Emulator also leads on device support (4 vs 2). Keep The Fly's advantage is iOS requirement (13.0 vs 17.0). On price and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Scorecard3 real differences · 7 level
Phosphor Emulator versus Keep The Fly: the parameters behind the verdict, then further details
ParameterPhosphor EmulatorKeep The Fly
PriceFreeFree
Rating4.7 (30 ratings) — better—
Positive reviews80.0% of reviews—
Number of ratings30 — better—
Update frequencyEvery 2 days—
AdsNo — betterYes
In-app purchasesNoNo
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, Mac, Apple Watch — betteriPhone, iPod
Requires iOS17.013.0 — better
Further details — not scored
Size81 MB36 MB
Age rating4+4+
DeveloperSquatchCraft LLCStratton Apps SL

In-app purchases

None

Phosphor Emulator

No in-app purchases

None

Keep The Fly

No in-app purchases

Questions

Is Phosphor Emulator free?
Phosphor Emulator is free to download, with no in-app purchases.
Is Keep The Fly free?
Keep The Fly is free to download, with no in-app purchases.
Do Phosphor Emulator or Keep The Fly have ads?
Keep The Fly shows ads; Phosphor Emulator does not.

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