Official solution

Level 15 solution.

Spoiler ahead: this is the completed grid.

Level 15Official solution · waddledoku.com
Completed grid

The answer

One perfect spot in every row.

Reading from the top row down, place the penguins in columns 10, 5, 7, 3, 1, 9, 4, 6, 2, and 8.

That places exactly one penguin in each row, column, and colored region, with no two penguins touching—even diagonally.