**Developing Playable 2048**

I'm focusing on implementing the core game logic for a playable 2048 experience. The 4x4 grid mechanics are taking shape, and I'm considering how to make grid size selectable, adding an interesting layer of complexity to the gameplay.

**Refining Game Mechanics**

My current focus is on perfecting the tile movement and merging logic across various grid sizes, including exploring custom board dimensions. I'm also implementing smooth animations for tile appearances, slides, and merges, along with score tracking and win/lose states.

**Designing Game Structure**

I'm currently focusing on establishing the foundational architecture for our 2048 game, specifically within the `index.html`. My immediate goal is to define the grid structure and the core game logic, envisioning the board as a 2D matrix of Tile objects.

**Developing Tile Logic**

My focus has shifted to defining the attributes of individual tiles, including their value and current position. I'm also detailing the mechanics for tile movement, merging, scoring, and spawning new tiles, all while considering win and game-over conditions. This work is crucial for building the game's core functionality.

**Implementing Visuals & Sound**

I'm now concentrating on bringing the game to life visually and audibly. This involves implementing smooth animations for tile movement and merging using CSS transitions and keyframes, alongside incorporating sound effects and music via the Web Audio API for a richer player experience.

**Examining Tile Logic**

I'm currently scrutinizing the `index.html` to confirm the tile sliding animation and board layout calculations. I'm specifically looking at how tile animation and position tracking are handled within the `renderTiles(isMidAnimation)` function, paying close attention to the `tile.row` and `tile.col` properties when `this.renderTiles(true)` is invoked.

**Implementing Smooth Transitions**

I'm now focusing on ensuring smooth tile sliding. The key is to leverage CSS transitions by reusing existing DOM elements and updating their `transform` property to the new position rather than creating new elements each time. I'll be inspecting how to properly manage tile DOM element persistence and update their transforms for fluid animation.

**Analyzing Merge Logic**

I'm currently examining the interaction between `this.renderTiles()` and tile merging animations within the `move(direction)` function. My focus is on how `tile1` and `tile2` are handled when they converge at the target `(positions.next.row, positions.next.col)`.

**Refining Animation Sequence**

I'm observing how the `mergedTile`, `tile1`, and `tile2` animate to their new position over 110ms. Post-animation, `this.tiles` is updated, and `this.renderTiles()` is called again, precisely when `mergedTile` gains `isMerged: true` and the new tile gets `isNew: true`, triggering the keyframe animations.

**Confirming 2048 Functionality**

I am confirming that the 2048 game meets the prompt's requirements, including customizable grid sizes and support for arrow keys, WASD, and Vim bindings for tile movement and merging.