Really nice concept and good mission.
Two minor suggestions:
1) Im the kind of player that at the very fist attempt never tries the most obvious routes and looks for alternate paths. I saw it was possible to jump trough shallow water directly east from the start, but mission instantly fails when landing on the isle in the middle with no apparent reason (no mechs, no alarms, nada... the mission simply fails instantly). Why leave a secondary route open on the map with a so punishing outcome in the first place? Is this intended?
2) The very istant my mech kills the challenger in the arena, he turns and immediately shoot the nearest of the guards, even if they are not turned hostile. Took me a few tries to time a well placed "stop all orders" and avoid this. It kinda killed the rythm of an otherwise very well designed mission. Isn't there a way to circumvent this kind of behaviour?
Have a nice day!
If you visit such an area with bandits and under the control of an arena master that will never play fair you are suspicious and never granted access to the arena. By design and logical.
Only pilots with big ego and lower skill levels will attack the guard by free will.
The selection of pilots and clear control of their action is the commanders job.
If one trigger-happy pilot aims/shots at the guards they are all over your units.