The amount of fluidity in character movement current present there seems unreal. Collision seems to be perfect, movement seems to be perfect, and control seems to incapsulate every control we have on our bodies and more. This requires significantly more than just art models, animations, and rigid bodies. It would require a physics engine on levels that current don't exist. However, even if the engine exists, the amount of control she has on her abilities (like transforming partially into a Mecha) is very specific and would require a good brain to game interaction to pull, and be insanely hard to implement (how does one implement everything the brain thinks of). In other words a lot of what's there seems to be completely infeasible. The level of interaction and control characters exhibit seems out of reach with current tools.