You must simply beat the game on Lemon (Easy). Trophies do not stack, so you'll need to play the game AT LEAST 3 times to earn all trophies.
Pretty straight-forward and should cause no issues to most gamers. If you think you'll have a hard time, check my solution for 'High in Las Vegas' to earn unlimited Red Gems, which will allow you to easily and quickly upgrade your health and firepower.