Here is the full list of all 54 Sekwere achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Collect 999 level completions on 6x6 board
Get 200 as highest level on 6x6 board
Collect 400 level completions on 6x6 board
Get 100 as highest level on 6x6 board
Get 42 as highest level on 6x6 board
Collect 180 level completions on 6x6 board
Get 20 as highest level on 6x6 board
Get 10 as highest level on 6x6 board
Collect 60 level completions on 6x6 board
Collect 20 level completions on 6x6 board
Collect 1400 level completions on 5x5 board
Get 200 as highest level on 5x5 board
Collect 700 level completions on 5x5 board
Get 100 as highest level on 5x5 board
Collect 380 level completions on 5x5 board
Get 42 as highest level on 5x5 board
Collect 142 level completions on 5x5 board
Get 20 as highest level on 5x5 board
Get 10 as highest level on 5x5 board
Collect 90 level completions on 5x5 board
Collect 30 level completions on 5x5 board
Collect 1600 level completions on 4x4 board
Get 200 as highest level on 4x4 board
Collect 800 level completions on 4x4 board
Get 100 as highest level on 4x4 board
Collect 400 level completions on 4x4 board
Get 42 as highest level on 4x4 board
Collect 200 level completions on 4x4 board
Get 20 as highest level on 4x4 board
Collect 150 level completions on 4x4 board
Get 10 as highest level on 4x4 board
Collect 50 level completions on 4x4 board
Collect 100 level completions on 4x4 board
Get 200 as highest level on 3x3 board
Get 100 as highest level on 3x3 board
Get 42 as highest level on 3x3 board
Collect 5000 level completions on 3x3 board
Collect 2000 level completions on 3x3 board
Collect 1000 level completions on 3x3 board
Change 2000 squares
Collect 500 level completions on 3x3 board
Change 1000 squares
Change 500 squares
Collect 200 level completions on 3x3 board
Change 100 squares
Change 42 squares
Get 20 as highest level on 3x3 board
Collect 50 level completions on 3x3 board
Change 20 squares
Get 10 as highest level on 3x3 board
Change 10 squares
Change 5 squares
Change square for the first time