Welltris - Alexey Pajitnov's (World?, 2 players)

Welltris is a puzzle game that builds upon the core mechanics of Tetris but introduces a unique three-dimensional perspective. Instead of a flat, two-dimensional playing field, players interact with a "well" that has four walls.

The primary goal in Welltris is to clear lines by completely filling them with blocks. Unlike Tetris where only horizontal lines are cleared, Welltris allows players to clear both horizontal and vertical lines.

Blocks, similar to Tetris tetrominoes, fall from the top of the well. However, the key difference is that players can choose which of the four walls (north, south, east, or west) the block will originate from. Once a block enters the well, it slides down the chosen wall until it hits another block or the bottom.

While a block is falling, players can move it left or right along the chosen wall and rotate it. The challenge comes from visualizing how the block will fit into the 3D space and how it will interact with existing blocks.

To clear a horizontal line, a full row of blocks must be formed across the entire width of the well. To clear a vertical line, a full column of blocks must be formed from the bottom of the well up to a certain height.

A unique mechanic in Welltris is the "melting" of blocks. If a block is placed in a way that it cannot move further down (i.e., it's "stuck" on top of another block or the floor) AND it's not part of a completed line, it will start to "melt" after a short delay. A melted block solidifies into the well's floor, becoming an obstacle that cannot be moved or cleared unless it's part of a line. This adds pressure and requires strategic placement.

The game ends when the well becomes too full, and there is no space for new blocks to enter and slide down a wall without immediately melting or being unable to be placed.

As the game progresses, the speed at which blocks fall increases, and the variety of block shapes might also become more challenging, demanding faster reflexes and more foresight.

Success in Welltris relies on careful planning. Players must not only think about filling horizontal lines but also consider the vertical structure of the well. Preventing blocks from melting is crucial, as melted blocks quickly fill up the well, making it harder to maneuver and clear lines. Utilizing all four walls effectively to position blocks for future line clears is a core strategy.

Welltris offers a fresh, brain-teasing twist on the classic falling-block puzzle genre, requiring spatial reasoning and quick decision-making.