We currently have two options to create a mech.
1. Call up the specific animations when they are needed (forward key starts up the walking animation, and continues it, releasing the key stops the walking animation and starts the slowing down to a stop animation, etc.)
Problem is this looks incredibly crappy for a mech.
2. Ragdoll mech, this will require a huge amount of time and mathematics but it might be doable. The advantages include that you can put more constraints and limits into the movements, disallowing the legs to spontaneously disappear and reappear into another position as it would using animation sequences. Also if the mech would be hit, it would get physical recoil, which would look pretty intense.