Quests in Final Fantasy are separated into two categories: main story quests and side quests. Side quests are even categorized further down into three types: hunting quests, regional quests, and only-for-fun. Main story quests involve around the story progression on Noctis, how he reclaims back his throne, and fulfill his destiny.
Side quests like hunting quests, on the other hand, do not relate much to the game story but gives player additional rewards. Regional quests are quest lines specified to certain places and locations. Only-for-fun quests do not give anything but fun to do.
From time to time during the story progression, a player is given 2-4 choices in a conversation. Although choosing any choice eventually leads to a similar conclusion, it comes with different rewards, mostly AP or EXP. Over 200 side quests are available in Final Fantasy XV. Completing the game perfectly can easily take more than 200 hours of playtime.
Final Fantasy XV has 16 chapters in total with many main quests in each. Main quests focus on Noctis’ destiny and his responsibility as the sole heir of the Lucis Kingdom.
According to Hajime Tabata, the first half of the game revolves around Noctis finding 13 royal arms hidden all around the Eos. Gameplay is like an open-world where a player can journey and make an exploration in anyway they want.
The second part of the game is more linear that a player is required to follow specific steps to help Noctis take back his homeland from an invasion of Niflheim and save the world from falling into the complete darkness.
Main quest locations and destination are marked with a red exclamation mark on a map. They can be completed one after another right away without any condition. It is possible to focus alone on the main quests and complete the game story without even having to do a single side quest. The game director claimed that main quest rewards alone are enough for character progression.
It should normally take around 40+ hours to complete the game story.
Hunting quests, marked by a yellow monsterish icon on a map, are additional sources of income helping a player to have enough gil for purchasing necessary healing items and equipment. They work like a monster hunt where a player needs to hunt down certain monsters and claim for rewards.
A list of monsters with rewards, including gil and item, and requirements can be found in any Diner NPC (Noctis and his party can eat here for additional food buffs as well) . Each NPC provides different monster lists. And each monster has different conditions. Some can be found all days and nights, some only during the day, and some only at night. The amount of rewarded gil decreases significantly when hunting the same monster for the second time.
A monster-hunting poster is another way of accepting a hunting quest. It can be found everywhere during the road trip. However, only one monster hunting quest can be accepted at a time.
Each monster also requires specific monster hunting ranks starting from one to ten. Completing a hunting quest for the first time rewards a hunting rank(s). When hunting ranks reached certain amount, more difficult hunting quests can be accepted.
Considering it is a great resource of Gil and experience for leveling, a player should check a hunting quest the same time they have the map updated from the diner NPC. Some monster location is located pretty close to the main quest destination making completing two quests within the same time highly possible.
It is not necessary to accept the same hunt twice unless its location is, again, near the main quest destination.
At present, not much information is revealed on a regional quest. What we have known so far is that this type of quest is different based on specific NPCs in each region. Weapon upgrade from Cid is an example of the regional quest.
Cid is located in Hammerhead. He is a friend of King Regis as well as his personal car mechanic. Cid is also the same person who repairs Regalia for Noctis and his party. From time to time, a player can upgrade a weapon with him by finding certain upgrading materials.
Regional quest is expected to provide an additional story to the main story quest as well. It should be about the whole events happened in Eos, Noctis’ relationship with other characters, the game background story, and more.
Since there seem to be different types of quest in the regional quest, it should come with different rewards. Some provides an upgraded weapon, some might be materials to customize Regalia, and some might be gear and so on.
This type of quest literately does not give anything. It does not provide any legit reward or story, but only for an entertainment purpose. The only-for-fun quests include fishing, chocobo racing, mini-games, and more.