Level design lol 

Level design :5
Player Control :5
Graphics tech:2
Art Direction :3
Music :1
Skund effects :1
Story and Lore:3
World Building:3
Gamepacing :4
Game Length:3

I wouldn't really consider that as a major element of gameplay.

Level Design: 5
Player Control: 2
Graphics Technology: 5
Art Direction: 3
Music: 2
Sound Effects: 2
Story and Lore: 5
World Building: 3
Game Pacing: 2
Game Length: 1

Suddenly nobody cares about graphic technology... come on guys! That sounds kind of unrealistic.

Anyway, art direction is always more important considering those two and it's a good thing people don't reduce their liking to games to their visuals. Good thing retro gaming is so trendy, too.

Level Design:4
Player Control:4
Graphics Technology:3
Art Direction:3
Music:3
Sound Effects:2
Story and Lore:3
World Building:3
Game Pacing:2
Game Length:3

Level Design: 4
Player Control: 4
Graphics Technology: 3
Art Direction: 4
Music: 2
Sound Effects: 2
Story and Lore: 3
World Building: 3
Game Pacing: 2
Game Length: 3

Level Design: 5 (The best games ever made have something in common: stellar level design. This includes puzzles, hazards, secrets, and challenges, and is directly related to pacing, below)

Player Control: 5 (Video games are defined by the ability for the player to engage with the game's programming; without player control, it's just video)

Graphics Technology: 3 (These are video games, so graphics matter. But as long as the graphics, frame rate, and physics are serviceable, I'm happy)

Art Direction: 3 (A cohesive art style has a way of bringing a game to life and bestowing it with a visual identity)

Music: 2 (Music can evoke the right mood and atmosphere, but it's tangential to video game greatness)

Sound Effects: 1 (Great sound design can add texture and flavor to video games, but, again, it's something that can be done without)

Story and Lore: 1 (A good story and mythology can frame and inform a great video game, but some of the best games of all time are devoid of narrative)

World Building: 4 (A living, breathing world with clearly-defined rules goes a long way to immerse the player in the game and provide plenty of meaningful interactions)

Game Pacing: 4 (A poorly paced game is a serious problem; players need to be regularly challenged and surprised by involving gameplay scenarios)

Game Length: 2 (Two Worlds can last hundreds of hours, yet it's a mediocre game; Ico can be beaten in an afternoon, yet it's a masterpiece)

I've bolded the sections that are most essential in terms of gameplay, in my mind the single most important feature in a video game.

Player control is obviously a major element, I would say level design is mostly about gameplay, and game pacing & SmokedHostages explanation of World Building could be part of it too.... I can't think of much else for gameplay, it's kind of an ambiguous term in a way. I guess it is about how the player interacts with the game world, which is mostly about controls & level design

Level Design: 4
Player Control: 5
Graphics Technology: 3
Art Direction: 2
Music: 2
Sound Effects: 1
Story and Lore: 3
World Building: 3
Game Pacing: 4
Game Length: 3