Some filters may not look great on all elements in game. The reason is that some textures are extremally small and may require a fallback to XBR2x or XBRZ2x filter, like character's eyes.
For example Bilinear Original looks great on mermaid's tail and hair style with its blurry, yet dithered effect. On the other hand it likes to break the eyes and torso.
Hold CTRL and scroll-up for zoom in.