The beautiful mountain BG from the second mission of Metal Slug 5, The zip contains the Sample level, Palette, ExGFX and Map 16
The dithered gradient in the sky somehow got messed up in the ripping process, and as a result, it is abruptly interrupted by random colors, ruining its continuity and smoothness. There are also two 8x8 tiles cutting off the sky gradient (tiles 203 and 20A to be precise).
Part of the submission unnecessarily uses palette row 4, which is used by important SMW objects, when it could be using palettes 0 or 1, which are often reserved for custom backgrounds (reminder that colors 08 and 18 aren't used by the status bar, as they're Layer 3 transparency and as such, they're fine to overwrite).
Your palmask overwrites the back area color even though it's not used by your submission.