The "Night Mode" itself is actually pretty useful. It takes advantage of the VDP's shadowing and highlighting ability. For all tiles on the Plane A High and Plane B High graphic layers, the VDP highlights those tiles. For all tiles on the Plane A Low and Plane B Low graphic layers, the VDP shadows these tiles. Sonic Team could then see if they got the highs and lows in their proper spot.
A lot of you know this already, a lot may not. So this is here for the general informing of everyone.
For more codes like this, visit my doc, the Genesis Sonic Code Database, at http://www.angelfire.com/vi/zgamesoftware/...onic/index.html These do not have the beta codes.