Emerald Hunt is a type of Single Player level in which the player tries to collect three Chaos Emeralds hidden in the map, similarly to Knuckles's stages in Sonic Adventure. Once all three emeralds have been collected, the game will automatically end the level – for this reason, exit sectors are not needed in Emerald Hunt maps.
Three emerald icon graphics will appear at the bottom of the HUD, representing each of the three hidden emeralds in the map. These icons act as an emerald radar, which the player uses to find the emeralds. The colors of each emerald icon, as well as the interval between each of the "beep" sounds played by the radar, indicate the distance from the corresponding emerald – as the player gets closer to an emerald, the color of the emerald icon for it on the radar changes, and the radar beeps are played more frequently. Once the player finds an emerald, the icon for the emerald found will disappear from the radar. See the table below for what distance each color and beep interval represents:
|Color||Icon||Beep interval||Distance from emerald|
|Gray||None||3072 fracunits or greater|
|Blue||1 second (35 tics)||Between 3072 and 2048 fracunits|
|Green||30 tics||Between 2048 and 1024 fracunits|
|Yellow||20 tics||Between 1024 and 512 fracunits|
|Orange||10 tics||Between 512 and 128 fracunits|
|Red||5 tics||Between 128 and 0 fracunits|
An Emerald Hunt map is made by placing at least three Emerald Hunt Location Things on the map. Up to 64 of these Things can be placed. The game will then randomly choose three locations to be used every time the map is loaded. This allows for complex maps that play differently even after numerous playthroughs.
|Game modes||Campaign • Ultimate mode • Marathon Run • Record Attack/NiGHTS Mode • Multiplayer|
|Gametypes||Single Player/Co-op • Competition • Race • Match/Team Match • Tag/Hide & Seek • Capture the Flag|
|Level types||Supplementary: 2D mode • Mario mode • NiGHTS|
Other: Special Stage • Emerald Hunt