Hi all, I would like to request a feedback for this concept I've been working on.

This is another variant of sudoku I've been playing around; though current puzzles are not too hard, but it feels fun and solid enough. The premise of the game is simple: You are given an 8x8 grid, which you need to fill in with numbers between 1,2,3,4,6,7,8,9 (no 5). The rest is similar with regular sudoku: no repeating the same numbers across, vertically or in any surrounding cells... However there's one twist: each 2x2 group must add up to exactly 20.

A solved 20x20 puzzle will look like this:

To try out the puzzle, I've made a web version of the game and uploaded a few puzzles; you can head over here to try: https://dwidasa-2e37f.web.app/

If you find the idea interesting, help me make it better and give me some feedbacks