Combine matching letters to climb the alphabet. Each merge makes a new, more valuable letter.
A + A = B, B + B = C, ... K + K = L (the classic goal). Keep merging past L for legendary tiles all the way to Z.
Each merge scores points equal to the new tile's power: B scores 2, C scores 4, D scores 8, ... L scores 2048. Highest letter and best score are saved locally.
When the board is full and no two adjacent letters match, the run ends.