Dragon Quest games in general tend to have banks, which take deposits of 1000 GP at a time. If you die, you don't lose any of the gold stored there. A definitely nice feature where deaths normally cost 1/2 of your total GP.
If, for some reason, you don't find all the keys...worry not! The Princess of Moonbrooke learns the spell of Click, which will open any door in the game. It is possible to use this to your advantage, seeing as how it can also open up 3 item slots for you characters.
Since MP restoring items are hard to obtain and unreliable and only one item that can revive a character, some items can replicate magic spells with no MP cost. The Power Shield will cast Midheal on the character who uses it as an item in battle, for example. This lets you save MP from healing and use it for other spells, like buffs/debuffs and Kazing.
Dragon Quest IV has an Iron Safe, an item which can be obtained by Torneko during chapter 3. It prevents a regular 50% money loss when being wiped out during battles, but you can't carry it over to latter chapters: the reason it exists is due to the heavy emphasis on getting enough money to finish the chapter.
An important part of Dragon Quest VII is finding stone tablets, some of which were placed in Guide Dang It! locations in the original Playstation version. While some still are placed in such locations in the 3DS version, the 3DS version makes finding them much less of a chore. First off, you can use a menu feature that will not only inform you of the tablets location, but it will also give you a hint. Then, when you go to look for it, the bottom screen (depicting the map) will not only have something glow if there is a tablet piece nearby, but if your tablet is on the floor, it will flash it on the screen.
Dragon Quest VIII does not have Iron Safes, but unlike other games, all four characters will be revived and completely healed after you've been beaten, making a game over less painful as you don't need to spend more money reviving them.
Dragon Quest X: Skills and spells have symbols describing what kind they are. (Red for attack, green cross for recovery, blue for buffs, purple for debuffs, and yellow for misc and field) This also carries over into the next game.
Losing to the final boss allows you to choose to go to the dungeon or go straight to his throne room, allowing you to skip straight to the final boss fight to try again.
Losing to any of the Mirror Bosses causes the game to give you your items back if you lost during a fight against them and you'll be respawned outside the mirrors instead of your last save point.
If you fail to defeat King Latem, the game takes you to the result screen regardless and the fight is counted as complete with your only setback being that you get no EXP or rank bonuses during the fight.
The refights before Edah Sohpix are easier than their originals: Der Gib spends more time in the foreground, reducing the amount of projectiles to reflect, Valgirt Nedlog skips its first phase entirely and Nomegoen seems to take more damage.
While managing hunger is key to both adventuring and building efficiently, having to worry about this while building up your settlements can get annoying; build a proper cafe/bistro however and so long as you're within your base your hunger is locked at whatever state it's currently in, allowing you to work at home without having to worry about food intake.
Early on in the beginning quests, you get to build a Colossal Coffer; a massive, magical treasure chest that can hold a lot of items and materials. Its most important feature is that you can access it from anywhere in the world, and it automatically receives anything you pick up when your personal inventory is full. This prevents the old problem in Minecraft-esque games of "my inventory's full, now I have to leave all this stuff behind".
In Terra Incognita, the other islands can be reset to their original states via the main island's Banner of Hope. This way, you will never be lacking for materials.
While you can no longer place teleportation beacons anywhere you want, there are far more fast-travel points available to you, and you can teleport inside buildings and caves.
Weapons and tools no longer have limited durability.
There's a dedicated button for swinging your weapon, and a dedicated button for using and switching between tools.
Tools do very little damage to enemies, and weapons don’t destroy objects. This prevents you from accidentally destroying your own village when fighting monsters in it.
Shortly after starting the first island, your inventory becomes MUCH larger than the first game, and you don't even need the Colossal Coffer this time!
If you have build requests or active blueprints your inventory and crafting screens will mark the items you need and how many are needed.
Gloves let you pick up, rotate, and drop individual blocks without having to hammer them.
After a certain point in the game, villagers can build blueprints for you (if provided the materials). In general villagers will do some tasks for you as the Base level increases, reducing the amount of micromanagement needed compared to the previous game.
If you need materials for your personal island, you can travel to a handful of smaller islands that randomly generate and will always have what you need. While you need to pay a fee in gratitude points to unlock travel to the island, you'll be able to travel there as many times as you wish after. In addition, completing scavenger hunts on those islands will unlock unlimited amount of a material at builder's stations, reducing the amount of grinding needed (and playing the Echo Flute on those islands will lead you directly to each of the items on the list without having to scour every square inch).
An update to the game allowed you to save three different Buildertopias, instead of just one.
The cladding and flooring items from the first game have been swapped out with the far more versitile Transform-o-Trowel, which lets the player instantly swap walls and floors with any other building material from their inventory as much as they want (instead of only working on dirt and converting it into one of several preset materials). It can later be upgraded to create walls just as easily.
When monsters attack as part of story segments, NPCs will instantly repair any damage done to the town once the battle is over.
