Darkest Dungeon 2 takes the combat of the first game and further refines it while giving us further glimpses into the story and setting established in Darkest Dungeon, overall it makes for a very enjoyable roguelite.

If you're new to Darkest Dungeon and are unsure which game to buy or have played the first game and are on the fence about buying 2, read on as I've attempted to list some similarities and key differences between the two games below, although with more of a focus on 2 as this is a review of the second game and not the first.

• Combat is turn based, with your group of 4 heroes pitted against 4 enemies.
  
• Turns in combat are decided by the speed of each character present, with faster characters acting first.
  
• Position determines what abilities a character may use and who they may target, for example Hellion's Iron Swan ability requires her to be at the frontmost rank and may only target an enemy in the 4th position.
  
• Dead heroes and enemies leave behind corpses that take up a position in combat.
  
• Heroes may equip alternate abilities allowing them to fill different roles, only so many abilities may be equipped at once.
  
• Heroes may equip up to two trinkets providing various benefits and maluses depending on the trinket.
  
• Heroes posses both a health bar and a stress bar, where enemies only possess health. Reaching 0 health means getting put into the "Deaths Door" state, afterwards any point of damage has a chance of landing a deathblow and killing the character, healing above 0 health will cause the character to leave Deaths Door and act as normal. Maxing out the stress meter gives a character a chance at having a meltdown/outburst of some form, taking damage and typically carrying some malus that varies depending on the outburst, or steeling themselves and becoming resolute, healing them and reducing stress.

• Features an almost X-Com like focus on building and managing a wide roster of characters, death means the loss of a character and having to train a replacement.
  
• A run takes the form of a prolonged campaign, with progression between missions involving upgrading your town to better equip and maintain your heroes, with the ultimate goal being to get your heroes strong enough to tackle the titular darkest dungeon and win the run.
  
• Characters exist as classes, you can and will have multiples of the same character in your roster and a party may double up on the same class.
  
• Missions involve dungeons crawls with varied layouts, as you traverse each dungeon you are met with various encounters such as interactable curios that give different results depending on the choices made/items used or combat encounters.
  
• Resource management is crucial to keep your heroes topped up in missions so as not to lose a war of attrition.
  
• Features a separate PvP mode, the Butcher's Circus. I cannot speak on how active this mode is at the time of writing.

• Features two game modes, Confessions and Kingdoms.
  
• Confessions plays like a more typical roguelite, with meta progression between runs. Permanent unlocks are acquired between runs using Candles obtained throughout the course of a run, speaking from experience the grind is pretty quick as so long as you're making good progress a failed run will still net you enough Candles for a large number of unlocks and upgrades.
  
• Kingdoms runs are self contained, in that unlocks from confessions and other Kingdoms runs do not apply, and take the form of longer campaigns (albeit still significantly shorter than a typical Darkest Dungeon 1 run) where you move your party and other heroes around a map, defending and upgrading Inns (acting as your various bases) with the ultimate goal being to progress a quest and defeat a campaign dependant boss. At the time of writing three different campaigns are available, with different unique enemy factions and quests.
  
• Missions in both game modes have you travel along branching paths between various points of interest and potentially facing encounters as you travel. Your party members may indicate a preference for certain paths, rewarding you with a stress heal or taking stress damage if you follow or ignore their suggestions, and heal passively as you travel.
  
• The game features a narrower but deeper roster where each character is an individual (the presets forms of classes from the first game alongside some newcomers) with a large amount of unlockable alternate abilities/customisations and whose backstory is explored throughout the Confessions game mode (doing so permanently unlocks new abilities for the hero). In Kingdoms, alternate abilities are instead purchased at Inns with the required upgrade.
  
• Heroes possess paths (subclasses) that you unlock through progression in Confessions, or again at upgraded Inns in Kingdoms, that can drastically change how they play and allows for varied team comps and synergies, making up for the inability to double up on classes.
  
• Death in Confessions means losing the hero for the rest of the run and receiving a replacement hero if you make it to the next inn, this replacement is selected randomly from the heroes you have not yet lost this run. Death in Kingdoms is configurable at the start of a run, permadeath is on by default on most difficulties, however it may be configured so that a dead hero respawns at a penalty or a fresh untrained replacement spawns after losing a hero.
  
• Heroes form relations, rewarding you with positive boons such as a heal or DoT removal when using specified abilities or randomly attacking alongside or defending eachother at good relations and at bad relations debuffing themselves or eachother when using specific abilities or doing/taking stress damage. These relations are influenced by the choices made by the player throughout a mission as well as items used while resting.
  
• After a successful mission in Confessions you arrive at an Inn where you may spend mastery to upgrade abilities, purchase equipment and consumables, upgrade and repair your coach, and use Inn items to heal, buff, or improve the relationships of your heroes.
  
• As previously mentioned, Inns play a different more important role in Kingdoms and are only located at specific points on the map. If you travel to a location without an Inn, you will instead make camp which allows you to use consumables as you would an Inn but does not feature a merchant or upgrades and has the possibility of a surprise ambush, as in the first game.
  
• Does not feature the Butcher's Circus.
  
• Combat is similar to the first game, but features new tokens and mechanics such as the combo token which sets up for secondary effects on the abilities of various characters and enemies. Stall tactics like healing have had restrictions placed on them so that they may only target characters under certain conditions, such as being below 33% health or having specific tokens applied.
  
• In combat consumables are equipped to and carried by party members in a dedicated slot, with each character able to carry only one type of item at a time (they may carry multiple of the equipped item however). Using consumables does not take an action.

If you're coming from Darkest Dungeon 1 and find that your favourite parts of it were the wide roster management and the dungeon crawling, and are explicitly looking for more of that gameplay then Darkest Dungeon 2 may not be for you.
If your favourite elements of Darkest Dungeon 1 were the combat and strategy, or are looking to immerse yourself in more of the games lore and setting then I can thoroughly recommend 2.
If you're new and were intimidated by the longer campaigns and roster management of 1, you may find 2 a bit easier to get into.