When pixel art becomes blurry the first thing to look is the “Filter Mode” in a sprite’s Import Settings. *It should be set to “Point (no filter)”. That’s an obvious thing and an easy one to find.

But sometimes it doesn’t help. Today I’ve stumbled upon it, and the other fix is really not much harder.

Look for “Max Size” parameter. It should be greater than the spritesheet size. Otherwise Unity will rescale it and ruin the crisp pixel art look that we all love and strive for.