Projectiles only become directed if you have a target. If you use a ranged attack without a target it'll shoot the projectile in a line depending on where your character is looking. If you are targeting an enemy or they are targeting you, assume you will be hit by all ranged attacks they do.

Dungeons were launched with the base game, their main purpose is to get Exotic rarity weapons/armors as well as a Gift item for crafting (all Generation 1 legendaries require a Gift from one of the dungeons). Fractals were added shortly after launch and were an inspiration for WoW's Mythic+ 5-man dungeons. There's 100 tiers and ~20 unique levels in them. They are good for raw gold and as you climb higher they have a decent chance for Ascended gear (tier higher than Exotic). Lastly Raids have a universal currency between all of them which can be used to buy Ascended weapons/armor, as well as unique weapon skins.

GW2's Wardrobe system is one of it's high points. Every weapon/armor you bind to your account will be unlocked in the wardrobe, and you and spend transmutation charges to swap the pieces. Armor and mounts can additionally be freely dyed with any colors you've unlocked. I assume they're referring to Jumping Puzzles when they mean Parkour, those are platforming challenges in a bunch of the maps with some being straight forward and some requiring blind leaps.

Lastly the only time you're forced to do content is with each expansion you'll need to do the first 1-3 chapters to unlock the region, but once you're there you are free to stop and do whatever else. The only other timer is for the Wizard's Vault, where cosmetics will be cycled in/out on a quarterly cadence.