Don’t switch the difficulty to easy when the game offers to do so at the beginning of the game. It’ll lock out the trophy and the only other option is to restart your play through.
Enemies and bosses aren’t too hard and this play through will mainly be getting the story-related trophies and the multiple other simple trophies. Use this play through as training for the next few difficulties.
- if you are offered to switch to Easy Automatic, REFUSE THE OFFER. The save file will remain in a constant loop of that difficulty and there is no other choice but to create a whole new file. As a result, collecting Blue Orbs and purchasing upgrades will be a wasted effort as it will NOT carry over to your new file.