Re: does the Killer Sudoku become "slow" over time?
I solved today's easy killer this afternoon and have just finished solving yesterday's easy killer and the difficult killer from the day before yesterday. In neither case did I experience any lag or sluggishness.
Potentially (but not necessarily) relevant: My setup is Windows 7, Firefox, uBlock origin* and NoScript (with necessary exceptions). As an extra challenge, I avoided using "pencil" numbers when solving these particular puzzles.
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