List of third-party OPK applications

This article lists third-party OPK-format applications built for the FunKey S. Freely downloadable from this page, these applications allow users to add additional functionalities to their devices. Once downloaded, these files are placed in any folder at the root of the device's file system, with the Applications, Emulators, and Native games folders available by default for file management. The application can subsequently be accessed from the Gmenu2x launcher, where it is sorted automatically by its type: application, emulator, or game. As the device's Instant Action autosave feature is implemented on a program-by-program basis, users must remember to manually save their progress in any third-party program that hasn't implemented Instant Action. Also note that while many devices use OPK as an application format, only OPK applications compiled specifically for the FunKey S are compatible with it.

Should you wish to build or modify OPK applications yourself, you may download a version of SquashFS configured for editing OPK applications on Windows here. After extracting the SquashFS folder from its ZIP archive, add the OPK file that you wish to edit to the folder and double-click the ''1. EXTRACT_OPK.bat'' file. This will create a folder called squashfs-root, containing files for the application's configuration settings, icon image, and binary data. Unless you have prior experience configuring OPK applications, however, it is recommended that you only modify the icon file, a 32-pixel square PNG format image file that represents the application in Gmenu2x. In doing so, ensure that the replacement icon file is also a 32-pixel square image, in PNG format, and named exactly as the original file was (icon.png is replaced with icon.png). Once you have finished modifying the application, return to the SquashFS folder and double-click the ''2. MAKE_OPK.bat file, which will apply your modifications to the submitted OPK'' file. After several windows pop up and disappear, your application will be modified and ready to be returned to your FunKey S. Note that if there are multiple applications that you wish to modify, you must do so one at a time. For additional instructions on how to use SquashFS to modify or build OPK applications, it is recommended that you join the FunKey Community Discord Server.

Applications
The following applications are any programs for the FunKey S that are neither emulators nor games. Alongside each application is listed a general description of it.

Emulators
The following emulators add to the capabilities of the FunKey S by allowing emulation of several currently unsupported systems and improved emulation of several currently supported systems. To give users a sense of how well these emulators function, each is rated from low to high for both overall emulation accuracy and speed. To improve the CPS2 emulation of SDL Retro, this configuration file should be placed in the /mnt/FunKey/.sdlretro/cfg location of the FunKey S file system. For PC-FX emulation, a PC-FX BIOS file must be placed in the /mnt/Funkey/.pcfxemu location of the FunKey S file system.

If you don't see the .sdlretro or .pcfxemu folders, your computer's Unix-based operating system is hiding hidden folders. To enable the viewing of such folders on MacOS, use the Shift+Cmd+Period key combination. To do so on ChromeOS, click the three-dot icon at the top-right of the Files application and select the Show hidden folders option.

Games
The following applications are freeware games that have either been ported to or natively developed for the FunKey S. To facilitate list navigation and game selection, alongside each game is listed its genre. To play the OPK ports of commercial games, one or more additional files containing necessary copyrighted assets must be provided by the user from their own legally acquired copy of the game. The data files of such games should be grouped together in a folder located at that game's listed file location. Games requiring several of a specified file type to run have an asterisk placed after the applicable file types(s). While Doom, Doom II, and Final Doom only require a single WAD file each, they can be modified with additional WAD files located in the same folder as the main WAD file. While Quake technically only requires its PAK0.PAK file to launch, to access the full game, its PAK1.PAK file is required as well.