Have a look at the below image. It's in .png format to avoid any .jpeg compression loss of quality. Do you notice how the image is different, depending on which floor you have currently selected? Floor B2 seems to have some kind of blur effect applied. What's going on here? This affects the entire screen. I also noted that the screen for B2 is moved a pixel over to the left and a one pixel thick line is present in the top right corner of the screen. Please check your GameMaker room settings.
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SpotTheBlurEffect.png [ 236.91 KiB | Viewed 5750 times ]