I put out a quick fix (v0.4.3, browser version only). The canvas now keeps hard pixel edges instead of letting the browser smooth it when your 125 % scaling makes the size land between two pixels. I could reproduce the blur on my side (125 % scaling, window or fullscreen), and it went away with this change. Could you reload with Ctrl+F5, check that the menu shows v0.4.3 at the bottom right, and tell me if the picture is sharp now, at the default size and when you enlarge it? If it is still blurry, please run the console line again in that state.