Changes

The NES ROM information isn't sufficient to describe the cartridge and emulate it, so emulators have to include the layout and behavior of these mappers in their code, while the ROM header tells the emulator which mapper to choose. So unlike with other consoles, no matter how a NES emulator is accurate, it still can't run newly discovered ROM dumps from cartridges that used an original mapper, hence claims some emulators are "inaccurate" because their unlicensed NES rom support is inevitably complete and still a constant WIP.

[[File:Retroarch_2013-08-16_06-32-24-62.png|thumb|250px|Example of faulty visuals that are exposed when no overscan is cropped. Note the blank blue area to the left and the green garbage on the right. On NTSC CRT TVs, these areas may or may not be visible]]Several NES games need their overscan to be cropped to look proper. Unfortunately, there is seemingly no standard level of overcropping. Many games appear to require different levels for best results. For example, SMB3 requires quite a lot of cropping, however the same level of cropping will certainly obscure the letters of the status bar in Castlevania games.

===Color Palette===

{{Main|Famicom Color Palette}}