Block Dropping Merge

It's 2048's merging logic dropped into a Tetris-style falling-block frame: numbered blocks fall one at a time, and lining up two of the same value merges them into the next number up. You can see the next block before it drops, which is really the only planning tool you get, so most of the skill is stacking with that preview in mind rather than reacting after the fact. Let the board fill up before clearing space and the run is over.