Letter Quest: Grimm's Journey Remastered

This will likely be one of the first achievements you unlock, especially if you're using a Scrabble solver. You are allowed to take damage, just as long as you finish the stage with full health.

If you want to get this out of the way easily, you can always get the last enemy down to low health, then use a health potion to refill your health completely, then defeat the last monster. Or, once you have your attack strength fully upgraded, replay stage 1 and spell a 6+ letter word and you'll defeat the only monster and unlock the achievement.