ClassicBoy Pro vs Nexen

ClassicBoy Pro is an Android emulator for retro games, with a ROM scanner and game database. Its maker describes about twenty built-in emulation cores for systems including PlayStation, Nintendo 64, Game Boy, NES, Super NES, Sega systems, arcade games, and Atari 2600. External plugins extend support to systems such as Nintendo DS, MAME, Sega Saturn, and PC Engine/CD. The app can scan selected files or directories to identify games for a browsable library, where users can locate or favorite them. Controls include touchscreen buttons, external gamepads, customizable layouts, gestures, and accelerometer input; the maker lists gesture and sensor controls as premium features. Other listed tools include adjustable game speed, cheat codes, save and load states, and game-data import and export. Wireless controllers can connect over Bluetooth. The free version includes on-screen buttons and gamepad mapping. The app is listed for Android and Windows through Google Play Games, but the listing does not show in-app purchase prices. It does not include ROMs, and users must have the right to play each ROM.

Nexen is a free, open source multi-system emulator for Windows, Linux, and macOS. It lists eight fully supported systems: NES, SNES, Game Boy and Color, Game Boy Advance, Master System and Game Gear, PC Engine, WonderSwan, and Atari Lynx. CPU and PPU emulation is cycle-accurate, with full coprocessor support listed for several SNES chips. Each game can have unlimited timestamped saves, a visual picker, and 36 rolling checkpoints at five-minute intervals. Movie tools support frame-by-frame recording and playback, rerecording, and imports and exports for BK2, FM2, SMV, LSMV, VBM, and GMV files. A TAS editor provides a piano-roll timeline, undo and redo, greenzone seeking, alternate branches, and Lua scripting. Debugging tools include a disassembler, memory viewer, breakpoints, trace and code/data logging, and a profiler. Nexen also lists rollback netplay and exports symbols, code coverage data, cross-references, and source maps to Pansy for the Flower Toolchain. Sega Genesis, Atari 2600, and Fairchild Channel F support remain in progress.