The Enigma 2 is a big shoe, and so it is not as flexible as traditional or performance neutral trainers, like the Wave Rider or Wave Precision. But it does flex more than other shoes in the premium cushion class. The flexibility might be limited by the Flex Controllers, which are two bands of reinforced carbon rubber Mizuno puts in the outsole. They connect the two sides of a deep flex groove, and are designed to limit the amount of flex in the forefoot. To be honest, they did not seem to add anything to the ride quality, and I question their value.
The Enigma 2 also has Mizuno’s patented cushioning system, the Wave plate, running the entire length of the shoe. The Wave plate is flexible toe-to-heel, but it is very rigid side-to-side. That, combined with a firm heel counter, should give you some pretty significant medial support through the gait cycle. I can see runners with a neutral gait or who overpronate slightly running comfortably in this shoe.