So yes. I managed to beat the first boss, Terminatrix, in Hard Mode, with Zero Shield activation. And not once, but twice. First for the badge, then second time for the video recording.
The first boss isn't take hard to do for the bloodless or zero shield achievement. So long as you keep your distance, the long range attacks are pretty slow and you have plenty of forewarning on when to dodge. Nonetheless, I've had to try quite a few times, because of silly mistakes nearing the end of the battle... including once when I've downed the boss, but stood too up front and when the dead body appeared, it slammed right into my avalon. There goes my badge sigh. Once I hit the 'strike' button instead of the dodge too... Other times the movement pad wasn't responding because my finger has trailed too close to the edge... The problems of playing games on the phone. My Christmas wish list...: A Mfi controller for the iPhone 6s.
Alright. Here's the video:
There's basically just three attacks from the boss if you stay as far as possible.
The meteors --> Big red marks on the floor. Run away or dodge them!
Fire breathing --> Watch the head of the boss, if there's smoke coming out, he'll breath fire so don't stand in the center. If you don't stand in the center, and he won't breath fire. Some games I didn't see any fire breathing at all.
The laser --> Red mark on the ground where you are standing. If you keep moving, it'll miss. Or you can dodge left/right.
If you move up closer, he'll smack you with his left or right hand. If you wish, you can move up front to taunt the boss, then dodge back when the hand comes smacking so you can use your melee attacks on the arm. I just played it safe for my badges.
Ark equips with ballistic damage would definitely help in getting those badges.