The overview map shows you all available opponents. As you start a new game, only the tutorial is available, but as you defeat opponents, new ones will be unlocked. When you have defeated all opponents on the first difficulty, the second difficulty is unlocked and all opponents can be fought again. At higher difficulties, you can still fight against all opponents from the lower difficulties.

This is what the complete map looks like, when all opponents are unlocked :

In this example, the play has completed both normal and elite difficulty, and has unlocked legend difficulty.
A number of opponents appear muted, these are opponents that are only available in the lower difficulties. Several opponents have a yellow glowing targetter over it, these are unlocked opponents the player still has to complete on the legend difficulty. One of these opponents has been selected, which has brought up the selection box. In this selection box, there is a 'Fight' button next to each difficulty that has been unlocked. The small yellow stars tells the player which difficulties have already been completed for this particular opponent.

Pages on the NULLL forum :
Ultranought forum.

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