I was just going to add this as a comment to the solutions already posted as they are all good tips, but it turned out to be so long that I figured I might as well post it as a full solution. It highlights some of the only difficult areas in emerald knight mode.
Good call on the battery upgrade (@OldChili360). Not game breaking on emerald knight really, but helps facilitate as speedy second playthrough. Two tactics I found very useful that no one mentioned:
1. Your jet throws don't have to hit enemies directly to destroy them. On emerald knight enemies tend to get in your face pretty fast and interrupt the jet attack before you get the throw off, but I found that if you chain dodge away as far as you can get, then just jump and do the jet construct while in air, they will generally just stand there and then your jet will plow through and annihilate everything except for the larger manhunters and the speedy little hoverboard guys. For the larger guys, punch them in the face with the mech, for the hoverboard guys at first I used the ring blaster, but then I found out what I felt to be a better way to handle them and also deal with one other important fight:
2. The rocket pack- with the lantern battery and construct upgrades you can spam the hell out of this and it doesnt matter where you are facing or how far you are really, you will hit the little speedy guys on hoverboards and everything else. This turned out to be amazingly useful vs the last boss fight during the phase where you are still using your normal constructs. He moves around very fast and getting in close can be very painful, and the arms and guys he summons can get quite hectic on emerald knight, but if you have fully upgraded construct damage boost and dodge around spamming the rocket pack it will home in and destroy the arms and hit all the hoverboard guys etc, siphoning in tiny boosts of health from the arms and filling your ring surge meter. And then, when only the boss is there, ALL your rockets will hit him, doing about 3% damage every volley. Just dodge and dodge again, lantern battery a bit when you get a second, but only a second because you'll need to keep dodging, then fire a volley after he does a slam or whatever. When you get a ring surge, get in his face and activate it and spam the hell out of rockets because if you have fully upgraded ring surge guardian you are invulnerable and uninterruptable during surge and your rockets will tear him to shreds.
Lastly, vs the big rock guardian on Zamora, I found the spinning maces to be pretty effective at chipping away at her while not leaving yourself open to much damage. And keep in mind when she slams her hand across the screen to cause the cave ins you can just hold your block shield and you will not take damage from the swipe. Killing the crystals she summons out of the ground can also reward you with small bits of health if you need it, as it can be a somewhat long fight.