Marble Sort Level 688 — Walkthrough and Solution

Level 688 is the lock and key mystery trap. The Lock and Key trap on Marble Sort Level 688 jams your belt unless you clear Brown and Orange first, then carefully crack the ice to reach Purple.

Level688
DifficultyHard
Priority routePink → Red
Watch forPink

▶ Video walkthrough of Marble Sort level 688, then the step-by-step below.

⚡ Quick clear

Pink → Red. Hidden boxes turn every tap into a guess.

Marble Sort Level 688 presents a Lock and Key puzzle where a golden lock at the top of the Top Tray holds four key marbles: Light Blue, Green, Pink, and Orange. The bottom receiving Boxes start with demands for Blue, Brown, Purple, and Orange, but the front row of the Top Tray offers Pink, Brown, Red, Orange, Black, and another Red. The board's layout features a central cross-shaped block that splits the Top Tray into left and right halves; the left side has a cluster of Mystery Boxes, while the right side holds Iced Boxes with Black, Red, Pink, and Light Blue visible through the frost.

Your initial moves determine success. The bottom Boxes are arranged from left to right as Blue, Brown, Purple, and Orange. The front row of the Top Tray provides Brown and Orange as direct matches, but Blue is hidden behind a Pink marble, and Purple is trapped behind ice on the right. The central cross prevents any mixing between sides, so you must manage your Conveyor Belt carefully to avoid filling it with unused colors.

Marble Sort Level 688 Walkthrough

The bottom row's left-to-right demands are Blue, Brown, Purple, and Orange. The front row of the Top Tray has Pink, Brown, Red, Orange, Black, and another Red, with a Blue marble sitting directly behind the leftmost Pink. The main trap is that tapping free marbles like Red or Black early clogs your belt, as they have no immediate bottom Box to fill.

The imbalance lies in needing Blue and Purple early, but both are initially inaccessible. Blue requires moving Pink aside, and Purple is locked behind ice on the right side. The key is to clear what you can, then take calculated risks to unlock the hidden colors without jamming your belt.

How to Beat Marble Sort Level 688 — Step-by-Step

Phase one: Clear the immediate matches

  1. Tap the front-row Brown marble to drop it into the second bottom Box.
  2. Tap the front-row Orange marble to fill the fourth bottom Box.
  3. Leave the front Red and Black marbles untouched for now.
  4. Tap the front-left Pink marble to move it to your Conveyor Belt, exposing the Blue marble behind it.
  5. Tap the exposed Blue marble to start filling the first bottom Box.
  6. Now you need Purple for the third bottom Box; it is trapped behind the Iced Boxes on the right side, so you must break the ice.

Phase two: Crack the ice on the right

  1. Locate the lower Iced Boxes containing a frozen Black and a frozen Red marble.
  2. Tap the front-row Black marble to match it near the ice, cracking the Iced Boxes.
  3. Tap the front-row Red marble to match the other frozen piece, thawing more marbles.
  4. As the front row clears, the bottom Boxes will cycle to demand Red, Orange, and Brown.
  5. Once the ice breaks, retrieve the Purple marble that was hidden behind it and drop it into the third bottom Box.
  6. With the front bottom Boxes cleared, turn attention to the left side and tap the lowest Mystery Box.
  7. Check the revealed color against your bottom Boxes; if it matches, send it down, otherwise leave the other Mystery Boxes alone until your belt has at least three empty slots.

Phase three: Unlock the top keys

  1. After clearing the lower area, the central cross barrier is exposed, and only the Lock and Key setup remains at the top, plus a Key Box on the far upper right.
  2. Tap the upper-right Key Box first; it usually contains a Brown or Orange marble depending on your earlier drops. Clearing it activates the first key sequence.
  3. The golden lock will open, freeing the cluster of Light Blue, Green, Pink, and Orange keys at the top.
  4. Prioritize clearing the Light Blue and Green marbles, as they have been blocking the top-left corner.
  5. Clear the remaining keys to unlock any final hidden columns.
  6. Sweep the rest of the board, keeping your belt clean to avoid jams.

Tips & tricks

  • Only tap Red or Black when you have a matching bottom Box ready; otherwise, they fill your belt with useless colors.
  • When breaking ice, match colors near the frozen marbles to thaw them faster.
  • Open Mystery Boxes only when your belt has space, as the revealed color might not match any current bottom Box.

Common mistakes

  • Tapping the front Red or Black early, which clogs your belt and blocks access to needed colors.
  • Ignoring the ice on the right side until too late, leaving Purple inaccessible.
  • Opening too many Mystery Boxes at once, overwhelming your belt with unmatched colors.

Marble Sort Level 688 FAQ

Why does my Conveyor Belt flood on Marble Sort Level 688?

Your belt floods when you tap Red or Black early because they have no matching bottom Box until later, and they occupy valuable space needed for Pink and Purple.

Which color do I clear first on Marble Sort Level 688?

Clear Brown and Orange first because they directly match the bottom Boxes, then use Pink to reach Blue.

How many moves does it take to clear Marble Sort Level 688?

There is no fixed move count; it depends on how efficiently you clear colors, but a typical run takes around 60-70 moves.

Do I need boosters to beat Marble Sort Level 688?

No, boosters are not required if you follow the step-by-step order and manage your belt space carefully.

What happens if I tap Red early on Marble Sort Level 688?

Tapping Red early fills your belt with a color that has no bottom Box yet, wasting space and making it harder to clear Pink and Purple later.

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