Arcade machines, historically designed for fixed commercial operation, possess limited native capacity for player-created custom game modifiers. Their primary architecture is built on dedicated hardware and read-only memory (ROM), intended to present a consistent, unalterable experience. However, several methods have emerged to facilitate customization, ranging from official features to unofficial modifications.

The most common official method was through physical Dip Switches located on the machine's main circuit board. These small banks of switches allowed arcade operators—and sometimes players, if given access—to adjust fundamental game parameters. Settings like the number of starting lives, game difficulty level, bonus life thresholds, and time limits could be toggled. While not "created" on the fly by players, these switches provided a hardware-level means of customizing the game's rules.

Beyond dip switches, some games featured hidden "test mode" menus or built-in cheat codes that could be activated by specific input sequences on the control panel. These codes could unlock special modes, grant invincibility, or provide other modifiers. This was the closest players got to in-game customization on original hardware.

For more profound modifications, the community turned to unofficial methods, primarily ROM Hacking. Since arcade games are stored on ROM chips, enthusiasts dump these files to create digital copies. Using specialized software, hackers can directly alter the game's code (the ROM) to create custom modifiers. Changes can include altering character speed, weapon strength, enemy behavior, and even graphics. These modified ROMs can then be played on original hardware using specialized replacement boards or, more commonly, on emulators on personal computers.

Modern emulators, such as MAME, have significantly expanded the possibilities for custom modifiers. They often include built-in features like save states, rewind functions, and macro tools that act as real-time modifiers. Furthermore, many emulators support cheat files or scripts that can be loaded to dynamically change game behavior, offering a software-based layer of customization that was impossible on the original hardware.

Ultimately, the original arcade machines were severely constrained by their hardware. True, real-time, player-created custom modifiers were not part of their design philosophy. The modern handling of such modifications is largely a product of emulation technology and the dedicated efforts of the preservation and hacking communities, who have reverse-engineered these classic systems to allow for the creative customization we see today.