There are five properties that can be set for a ROM in corn's INI file, detailed below.

N. B. As of v0.29 Corn can autodetect "GUcode" and "GEngine". This means that, technically, the INI is no longer needed. However, it is still usefull to have one, because it can give compatibility information, the games' full titles and helpfull comments for the user.

Just to be clear about this, in Corn v0.30 (and above, I presume) an INI can reduce compatibility but not increase it! For example, setting opt1=1 in Mario64 in v0.30 will cause a crash! Just make sure you have the right INI for the right version of Corn.

Variable: "GUcode", possible values: [0,1,2,3]
[variable valid for versions 0.20, 0.29]

This chooses the Graphics "ucode". It is "fatal", so the wrong setting will cause an instant crash. If not set, defaults to 1.

Variable: "GEngine", possible values: [0,1]
[variable valid for versions 0.20, 0.29]

This selects the graphics engine. 1 is slower but higher quality. 0 is faster. This setting is not "fatal", so a game will run with either. If not set, defaults to 0.

Variable: "Opt1", possible values: [0,1]
[variable valid for versions 0.20, 0.29]

A speed optimisation. Setting to 1 will give a slight speedup, but may also cause the game to crash to the emulator. If not set, defaults to 0.

Variable: "Title", possible values: anything!
[variable valid for versions 0.20, 0.29, 0.30]

You can put the full name of a game here, if not set Corn will just use the ROM's header. Case sensitive.

[variable valid for versions 0.20, 0.29, 0.30]

Variable: "Comment", possible values: anything!
[variable valid for versions 0.20, 0.29, 0.30]

You can put text here to apear in the GUI, to notify the user of something. Case sensitive.