Helios, is a flyer type mech with energy based weapons. Its best used during the day when its able to access the abundant energy from the sun, where it opens up its collection wings to fire its hyper-precise railgun.
There's no articulation in the feet! NONE! That being said, if the Armour panel at the front of the shin were to be able to slide upwards as the foot was depressed into the ground during a walk cycle, that might remove some of the problems... its just that I'm not sure how sturdy it would be, planting all that weight onto one finite point as the Mech's weight is shifting through it's joints might not work... I don't know. If sir is aiming for even an air of realism in his designs, it might be worth looking up some of the Gundam designers internal mechanics sketches and so forth and using them as a base line or reference ever now and again. Not for design aesthetic mind you, but for the mechanics and articulation needed in Mecha.
OK, that was not in the description and could not be readily observed from the design itself. However, if this is the case then articulation in the feet specifically would be unnecessary and utterly superfluous! That does however beg the question, why does it need legs at all? If they serve no purpose save for landing gear and stabilizers, then perhaps, from a real world stand point (Admittedly this is an assumption based on the fact that real world Physics, design ethic, plays ANY PART in something like this! which it may or may not depending on your own preferences.) something else might prove to to be more suited to the task than a pair of legs.
It does need some more refinement however, that's a given and I'm eager to see what you guys come up with next on this project.