For example, expanding an NES ROM may be difficult or even impossible due to the mapper used by the game. The difficulty in doing this varies depending on the system for which the game was made. This limit can be overcome through ROM expansion, whereby the total size of the ROM image is increased, making room for more content and, in turn, a larger game. Generally speaking, a ROM hacker cannot normally add content to a game, but merely change existing content. As of today, various tools exist to alter the music of games which use the SMPS engine ( Sonic the Hedgehog games in particular), and many of them made their way to the Steam Workshop. A utility known as the N64 Midi Tool was created to edit the sequences that the majority of Nintendo 64 games use, though it does not cover the first-party N64 titles that use a slightly different engine, such as Super Mario 64.Several Mega Drive games use a sound engine unofficially known as 'SMPS', which has been researched for decades by many hackers. Various other utilities were created to work with the engine such as Sappy 2006.Another instance of the same engine being used between games is on the Nintendo 64, in which most games use the same format although they use different sound banks.

The program SapTapper can be used to hack Game Boy Advance music data, however, as many Game Boy Advance games use the M4A Engine (also called 'Sappy Driver') for music. As music cracking is very uncommon, many hacks do not have any ported/composed music added in. Music hacks are relatively rare, due to the wide variety of ways games store music data (hence the difficulty in locating and modifying this data) and the difficulties in composing new music (or porting music from another game).

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