(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
Can your brain go back and forth to handle all the increasing/decreasing entries in this Sudoku variation by clover!?

PDF

or solve online (using SudokuPad)

Theme: UP + DN

Author/Opus: This is the 157th puzzle from Clover, part of the Genuinely Approachable Sudoku (GAS) team.

Rules: Standard Sudoku rules (insert a number from 1 to 9 into each cell so that no number repeats in any row, column, or bold region). Also, numbers must alternate between increasing and decreasing along the gray lines (e.g., a valid sequence for a gray line could be 2937186 with 9, 7, and 8 as high points and 2, 3, 1, and 6 as low points).

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 6:00; One party hat (🥳): 11:00. All other solvers earn a 🦕: upbeat Uteodon.

Thomas Hits the GAS (highlight to view): 2:44, with SudokuPad replay file shared as a download for now (requires loading via settings menu with improvements expected before people should use this regularly).

Solution: PDF; solving video with explanation to be added later from GAS team.

Note: Follow this link for other less common variations of Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Daily GAS discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.