When you wrote "Good idea with the letters, but perhaps not necessary. People are happy with simple numbers. Just look at Sudoku which doesn't use A to I", I thought you hadn't noticed my mention of the larger grid, which was really the main point of my comment and maybe I should've worded it differently. Though if you'd begun your comment differently, i.e. "Good idea with the larger grid, but perhaps the letters aren't necessary. People are happy with simple numbers. Just look at Sudoku which doesn't use A to I", I wouldn't have felt the need to reply to correct a perceived communication mistake.
It's interesting that log_2 2028 is just above what you can represent in a single digit. That's very close to merging two 9s.
I'd like to actually see someone pit x, log_2 x, and letter(log_2 x) against each other in an A/B test of the game. The latter two are simpler, but the former might be more exciting, because of bigger numbers.
Good for beta testing it.
Unlike with Threes, there's no real reason to use numbers since they're all powers of 2. If you used letters (A, B, C, ...) you could market it to non-HN sorts, and have a version of the game in a 5x5 grid, or, more to the point, in a 6x6 grid with letters A to Z. Most people in the world know the order of letters in English.