The most essential survival tactic you will need is how to block/counterattack. You will probably never need to heal if you know just when to block an enemy's attack. This is key to defeating the Silent One without using any healing items and goes the longest way toward never dying in battle.

Fleeing is a lesser but important tactic, specifically as relates to the summonable support characters. The time it takes for each support character to be ready for battle again does not refresh between battles--therefore, in order to max out Fuchsia's damage potential, you will need to summon Fuchsia as many times as possible. This can mean summoning Fuchsia, then Fleeing the battle before all the enemies have been defeated, which will refresh the enemies but it also increments Fuchsia's damage counter. (Fuchsia's summoning interval does increase as damage goes up, so you will have to balance out whether you will need quicker rounds of weaker attacks or, more likely, the strongest attack possible for the single round Fuchsia will likely be able to be summoned.)

Finally, smash the hell out of everything you can find. CONSTANTLY. Crates and garbage cans contain items, but they also respawn when you leave an area. Especially since enemies do not randomly appear, it is VITAL that you stock up on items before every battle, because there is absolutely no advantage to depriving yourself of a key healing item or boost.

Obviously, you will have an easier time getting achievements based on fighting if your characters are the best fighters and the enemies aren't. A short list of things that will help:

- Choose the lowest difficulty ("be gentle"), even if it feels like cheating (it totally is, but you just want the achievements, don't you?).
- Save after EVERY battle in which you don't die. If you die, go back to the prior save and try again.
- Similarly, save after every battle in which you get a qualifying Overkill, and start over if you miss your chance. Be sure to do this for every single weapon upgrade, or you will just be throwing away potential stats.
- Flee as needed to prepare the support characters for summoning before a major battle. This may feel cowardly but will NOT count against Immortal, so take advantage of it if you find yourself losing!

This is tedious, I know, but achievements pay no attention to how long it takes you to get them!

The Dossier will provide key information for defeating enemies in the game, most noteworthy being that The Silent One is vulnerable to explosive items (specifically Hot Toddies and Dynamite, but Explosive Clown Noses seem to work just as well). Because using items is fast, your characters will be able to toss items so quickly that The Silent One will not have a chance to do anything for several rounds. The first thing you should do is use a Siege Brand Armor Eater (Defense -100%) and summon any of the support characters that are ready. In rapid succession, your next available character should throw any explosive items in your inventory until they are all gone. When the first support character has attacked, summon the next one. Even T. Kemper (the cat) has a small chance of attacking for 999 damage--do not just ignore him, since even his basic attack will buy you precious recovery time. On the easiest difficulty, this should get you most of the way through The Silent One's first form. You may have to block one or two attacks, but this is better than relying solely on attacking.

The second form is slightly easier to manage--I find the attacks more predictable in terms of knowing when to block. If and when the Defense -100% potion has worn off, use another, and combine this with using TEC-TONIC Brand Strength Beverage (Attack +75%) on your attacking characters. I find it easier to use the player character's and Gabriel's special attacks than Tycho's, especially since Tycho is the slowest, so I reserve Tycho for using items, but this is up to you. You can use Team Up special attacks if you have trouble with the mini-games, but if you can regularly get full damage with individual attacks, it will deal more damage for the time involved than a Team Up will.

The Silent One's third form will focus primarily on attacking one character at a time with Personal Attention (tentacle whip attack). Be sure to have your item character regularly use Dr. Hardd's Liquid Armor (Defense +100%) on the one being attacked. If the target is one of your attacking characters, be especially vigilant about blocking, as Personal Attention has an Attack -75% effect on it.

On the easiest difficulty, it is theoretically possible to get both Immortal and Silent, But Deadly achievements in the same fight, but in a pinch you may have to choose which achievement you want to get first, then try again for the second. If you need Immortal, don't hesitate to use healing items on characters who are dangerously close to dying. However, if you need Silent, But Deadly, don't freak out too badly if one of your characters dies just before The Silent One does (I got the achievement even though Tycho died right at the end).