The House of the Dead III

This is the mother of the House of the Dead 3 trophies. To get a Special Agent ranking you need to play the game from beginning to end (Free Play Survivor) getting an overall SS Rank. To get the SS rank you need to have 4 S Ranks and 2 A Ranks between the 6 chapters (Chapter 0 to 5). Here are some tips:

#1 - Accuracy counts, try not to miss or go for shots when you are moving too much
#2 - Go for headshot, they give more points and kill faster and you might get Twin Shot bonuses.
#3 - TIME MATTERS, seconds can mean everything, try to complete the level as fast as you can
#4 - Shoot zombies when they are down, it helps you move quicker and you get points doing so
#5 - Score matters to some degree, I was going for all hidden score items I could.
#6 - Always be shooting bosses (except Fool) because it adds to your score even if you deal no damage.
#7 - Avoid getting hit, this greatly reduces your score.
#8 - USE ALL 4 TRIGGERS ON THE DUALSHOCK 3. Hitting L1, R1, L2 and R2 at the same time will make you shoot 4 shells at once. This is critical to beating the bosses without getting hit.

Those tips in mind, to get the S rank you will need to make sure you don't fail the rescue sequences in that chapter, get a lot of headshots, have good accuracy, complete the level as quick as you can and avoid getting hit (you can take hits but it will significantly decrease your chance to get S ranks. You can pretty much avoid hits until Curien, where you can take a few hits and still get the S rank).