Never Gonna Let You Down Badge method that work for me: Floral-Radar-Fixed and TAKE YOUR TIME. At the beginning you have to be a little bit fast to get more yellow but after, take your time to see the red coming and avoid them. So my method was not to rush and go crazy with the mouse, but to be constant.
It would have been better if we would have more space to make the shop look nice, all I could think was to make it look efficient and the result is not easy on the eyes.
It took me 30 mns to know to press SPACE for the hero to fight in game and SHIFT to swap weapons. But at least I didn't lose fights because my unit were strong.
Medium badge isn't that hard. Look for clothes / weapon with the blue background with 100/200/+ damage bonus. I got them fighting rogues, later in the game.
The way I beat Forged Metal. With fire Warriors (armor) and Wizards (debuff). And poison Trainees (debuff). I put them the best accessories I could find from stores. Low cost for paving gloves is good too, have one.