Before the 이 part and the ㅏ part, the part with the 'k' sound is sharper, cleaner, and more pointed up with a sharper and cleaner line through it and a hook on the bottom. Same for 케. But somehow not 코. Why is that?
The characters in the first row always appear to the right of the first character in a syllable.
The ones in the second row always appear below the first character in a symbol.
The dimensions of that first character are different when paired with a character from the first row and when paired with one from the second row. The idea is to make all syllables occupy a similarly-spaced imaginary square.
This is not unique to ㅋ. Compare:
In the syllables on the right, the first character is shorter and wider then it is in the syllables on the left.