1. Shields are not armour, they are a tool, despite that they still mimic the usefulness of armour. Historically it was rare for a shield to be held face on, but at an angle, so blades and other heavy strikes glance off the surface. Same element is in play here. 

2. You don't recall the Mech literally flinging itself backwards into the wall again? Do you think that would make moving around easy?

3. Higan's grab was pretty intuitive, there's only one vulnerable point on his Mech, he made a grab for that exact area and threw the Mech's weight backward, your character somehow attacked that same area (while overextending something fierce, unless Slimy is a master of rock-fu) and ducked under the grab. (how that prevented its arm from being snatched, I do not know, presumably you just ignored that the grab was designed to catch whatever part of Slimy was overextended.)

4. Actually your ineffective attack was just a poor move on your part, allowing for Slimy's knowledge of the Mech's weakpoint you should have used a better tool, as I explained. If you had struck the optics directly rather than trying to smash it through the armour we wouldn't be having this conversation.

5. Why would I suddenly start using the word lens suddenly? The picture of what the Mech's optics look like are handily shown in my reference picture, it was never hidden. I'm just using the word lens now to point out what should have been targeted.

And your counter

1. Making that move based off reactions alone is even more unbelievable, it did in fact counter itself. You quite clearly had Slimy wrap itself around the right leg and launch itself forward through the legs, it then completely reversed that momentum to crawl around the left leg and round the outside instead. It's momentum would be naturally carrying it towards the right leg because that was what it wrapped around, and certainly not the complete opposite direction.

2. Actually, my character's Computer Systems with their ability to analyse materials are quite clearly listed, not to mention the numerous vision modes it holds. If you had not lied about your character's initial location I wouldn't have even needed the anomaly radar, as the Electric vision was perfectly suitable and would have detected your character immediately had I any knowledge of where it was in the forest.

3. Obviously, echo-location does not allow one to discern the nature of objects, only the rough shape. How your character knew the slight protrusion on the top of the Mech was a 'window' is really anyone's guess.

4. It certainly seems to be, considering it's actually longer than the Mech is tall it's doing a good job at tucking all its body parts in places most convenient for it.