Bumping because I just finished a plat playthrough and thought I would share my tips which differ from the trophy guide and FAQ.
The FAQ in question is
this one
And the trophy guide was
this one
SMALL BLOCKS IN 1ST PLAYTHROUGH
Well for instance, don't worry too much about doing events which give you small blocks ( the blocks carry over between playthroughs and are used to purchase swords which also carry over between playthroughs) in your first playthrough, I think there are something like 38 you can get per playthrough, BUT they are also a random drop from two enemies, dragons and crystal slime and there is a really easy place to farm them in your From Mode (hard) playthrough. So just collect 20 at a minimum in your first playthrough so you can buy Excalibur before starting NG+ as that sword is better than every other sword you can get except for the Giga sword which you only get access to just before starting the final temple in every playthrough, so that makes early From Mode playthrough much easier. If you have extra small blocks, the next weapon you should buy is the mage sword which when equipped lowers the cost of casting spells by 1 MP. All of the rest of the swords are not that useful so purchase them in whatever order you want.
FARMING SMALL BLOCKS IN FROM MODE
Once you have the freeze power you can farm small blocks 3 screens over from the starting location in From Mode really easily (the enemies do not appear in this location in normal mode), it is also a good way to make money because if the dragon or slime doesn't drop a small block it will drop 100 coins instead. Use that gold to level up your giga sword, first with pierce, and then length and width (I recommend not farming for blocks till you have the giga sword near the end of your From Mode playthrough) So that you can farm for small blocks and gold faster. Until you can get your giga sword to a suitable length, a good substitute is the maxed Excalibur. I maxed pierce, spin, and damage, with a few points in width and the rest in length so that it can reach to the end of most screens.
https://www.youtube.com/watch?v=tMLBS8uSJ9A
FARMING GOLD
Once you finish collecting enough small blocks to buy all the swords there is a more efficient place to farm for gold (it will take a LOT of gold to max out the giga sword (a trophy requirement, something like 48K gold). Cast frost magic, enter the screen, thrust once with giga sword to kill the enemies, then a second time to collect all the gold then exit and re-enter the screen.
https://www.youtube.com/watch?v=KezVE_ZS7Q4
PLAYTHROUGH ORDER
You have to do 3 playthroughs to plat the game. Normal mode (upon completion unlocks From Mode), From Mode (double damage against you, tougher bosses, and extra enemies all over the map), and Spelunker mode (normal mode enemy layout, except 1 hit will kill you) The Trophy guide recommends doing the 1-hit Spelunker mode playthrough second so you can accumulate more small blocks as you need 88 over the various playthroughs to buy all the swords, but since you can easily farm small blocks in From Mode I decided to do it second and save spelunker for last. Saving spelunker mode for last also guarantees you will have access to the mage sword at the start of the playthrough which is helpful as you will be using the freeze power a LOT in your spelunker mode playthrough. Sword upgrades also carryover between playthroughs so if you max out the Giga Sword in your From Mode playthrough (where money is much easier to make) that will make conquering the final temple in spelunker mode much easier.
BESTIARY
The trophy guide also recommends not doing the bestiary till the From Mode Playthrough, The bestiary is a giant book, you hit an enemy enough times with it (varies, the more difficult the enemy the more times you have to hit it) and eventually it is "booked" and you get an entry in your journal with information about it. You have to book every enemy and boss in the game. Since you take double damage in From Mode, I completed as much of the bestiary as I could in the first playthrough (especially the bosses, which you can replay by re-entering their chamber and clicking on their statue, as they have more robust attacks in From Mode).
The book damage is pitiful, but the damage scales up when you have more powerful swords equipped. On enemies that require a LOT of hits to book, but are not that durable (like the crystal slime) it is actually possible to kill the enemy before it is booked with just book strikes. So always equip the wooden sword (the weakest weapon) before trying to book an enemy. Also note, the enemy has to take damage in order for a book strike to count toward the required total. If, for instance, you hit a knight while his shield is up, it doesn't count toward the total. You also cannot book a frozen enemy as 1 impact from the book will kill them.
Since the first playthrough is very likely your no death playthrough, as soon as you successfully book a boss, save immediately during the boss fight. That way if you die and have to reload the save from the title screen, when you restart the boss fight you won't have to start from scratch, hitting the boss to rebook it again. The only place that doesn't work is on the final boss, you have to book and beat both bosses without dying as saving is disabled during the fight. What you could do is only worry about booking the second final boss, then once you have collected every other entry replay the boss and book the first final boss, that way the bestiary trophy for collecting them all will pop without having to beat the second final boss again, Trying to do both in the same boss fight was extremely tedious as every time you failed you had to rebook the first boss again The bestiary entries are saved between playthroughs.
GO EVERYWHERE TROPHY
There is a trophy for entering every map (overworld map screen, boss temple, boss chamber, house, and cave). I would recommend saving that for your From Mode playthrough (the collect all swords playthrough) since you have to go pretty much everywhere to do all the events. I would recommend printing off the below map and then crossing off items you collect and caves that you enter as you go so that you don't have to retrace your steps everywhere in case you miss a cave.
[customspoiler=map]
[/customspoiler]
If the image doesn't work use this link, it's the second, more colorful map
http://www.gamefaqs.com/ps3/971481-3d-dot-game-heroes/faqs/59492?single=1#section123
BLOCK DEFENSE MINI-GAME
The FAQ's guide for the tower defense clone mini-game Block Defense is WAY too conservative with spending money (which you get for killing enemies), if you follow his directions by the letter you will likely fail. Instead do pretty much everything he says a step early. If he says "build, then don't build anything in one wave and then in 2 waves build a tower", then build the tower (at least level 1) 2 waves early, you won't run out of money. At the end of every wave you get bonus money (starting at 5%) on money left in your wallet unspent. Every 4 waves will end with a tough enemy type which will give you a crystal to buy a new tower type OR an extra +5% to bonus money. His standard template is to buy four bonus ups, then after the 20th wave, buy slow tower. This makes wave 17-20 needlessly difficult. Buy 3 bonus ups, then buy slow tower after wave 16 and drop one or two near the start and upgrade to lvl 4, then buy bonus up after wave 20 and you will be fine for cash.
BLOCKOUT MINI-GAME
Another minigame is the game's breakout brick breaker clone, Blockout. The guide recommends exclusively using your shield to knock the ball back at the blocks, but this causes the ball to speed up more and more after enough strikes against your shield. Striking the ball with the tip of your sword causes it to slow its speed back to default AND go (more or less) straight up regardless of the angle it was traveling toward you. This is quite useful to angle the ball up a 1 wide hole or to direct the ball to the last block remaining on the board.
DASH CIRCUIT MINI-GAME
A time trial race, thankfully there are only 2 of them, you have to complete 3 laps under a certain time. Once you start dashing you won't stop and will slowly pick up speed, moving faster and faster. If you crash you will fall to the ground in a one second animation and then have to restart your dash. If you find yourself moving too fast to process you can manually stop your dash by pushing the d-pad or analog stick in the opposite direction you are traveling (ex. If you are traveling south, press up on the D-pad and you will stop running. Then you can immediately restart your dash at a more manageable speed. Stopping and starting is much faster than crashing and having to restart so feel free to stop and restart dashing before a difficult turn. The first one isn't two bad as it is short and is mostly a square, but the second one is long and has several turns. You have to beat the second race in under 65 seconds.
You can press select to pause the game mid-race in order to retry if you have made too many mistakes, but you can also abuse this to make the race easier as the clock also stops while on this menu. When your character is close to a turn, press select to pause the game. If you timed it right that your character is far enough forward to clear the turn, you can change the character's running direction while paused by using the analog stick. If not, put your thumb above circle and your other thumb above select. Press Circle to cancel pause and almost at the same time, press select again to repause. Inch along until you are ready to turn. You can cancel your dash while paused by pressing the analog stick in the opposite direction you are currently facing. If you have paused where you just barely haven't cleared the corner yet, but another unpause and pause will cause you to crash into the wall. press circle to cancel pause and at almost the same time press in the direction you want to turn on the d-pad. You will take one step forward (clearing the corner) and then immediately turn.
I did a combination of inching, and manually cancelled dash on the place shown on the right side of the map in this video. He does that because there is a 1 tile wide sweet spot on that straightaway in which you can dash through that leg and pass the trees on your left and right. If you dash around that turn you will have to make a sharp turn south and then west to make it through that straightaway. There is a similar one 1 tile wide sweet spot at 36 seconds in the video with a row of palm trees to your south and houses to the north on the left side of the map. So I sometimes manually halt the dash there at the turn, walk around the turn, press flat against the palm trees, and restart my dash again facing west.
https://www.youtube.com/watch?v=jW9mWnbm94I
I also created an all white block character in the create a character mode and entered the codes to stop walk swaying like in the below video. One thing I added to the white character was a series of purple tiles on the top of the character forming an arrow pointing in the same direction that the character is facing.
https://www.youtube.com/watch?v=MaL7xRMfvw8
All mini-games have to be perfected in your "collect all swords" playthrough.
Personally I stopped caring about trophies/achievements when I realized they were making the game into a chore rather than fun. I'll do fun challenges, but if it gets too tedious or frustrating, I say, "I'm out."
