NG++ is definitely harder, it will really test you on everything you know about the game, especially your mechanical knowledge and how well do you know your ac. That being said, in terms of bosses, NG++ final boss was the hardest for me to clear. Normal sortie mission wise, the escort the weaponized mining rig mission really got me wondering
Chapter 1 Combat Logs. Mission. Combat Log. Mission 4: Destroy the Transport Helicopters. 1 Silver Combat Log: Examine the middle of the buildings, on the top platform, where four helicopter targets are located. Mission 5: Destroy the Tester AC. 1 Silver Combat Log: Destroy the target. Mission 6: Attack the Dam Complex.