Why should the one-capacity boxes move first in Level 39?

They occupy the central slots needed by the larger side-feed pieces, so clearing them preserves the middle for the later route.

How do the side trays affect the solution?

They are live entrances that can add cats during the run; leave their approach lanes open until the large lower boxes are ready.

Catdom 2: No Timer level guide

hard 9 colors

Catdom 2: No Timer Level 39 is a side-feed board where the one-capacity center pieces must clear before the large green, pink, and orange footprints.

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Slide the blue L through the upper-right route into the blue cats and continue until its visible capacity reaches the late 2/1 state.
Move the yellow vertical box along its up/down column into the yellow group, leaving its reduced state away from the center.
Route the purple bar through the central-left lane into the purple cat, reducing its label from 2 to 1.
Use the red and teal one-capacity bars through the right-middle slots, then move the white vertical box through the lower-center column.
Bring the green L up the left/lower lane into the green cats while keeping its long arm away from the left tray.
Move the pink square through the lower-left lane into the left pink tray, then route the orange square through the lower-right lane into the orange tray.
Finish the remaining teal, green, pink, orange, yellow, and blue reduced states through the open edge lanes until the Well Done! screen appears.

Colors in this level:

Yellow, Green, Blue, Purple, Red, Cyan, Pink, White, Orange

Do not park the pink or orange capacity-4 boxes across the central crossing before the one-capacity states clear.
Do not close an arrow-marked vertical column while a side tray still needs to feed the board.

Clear every one-capacity center box before touching the four-capacity side-feed boxes.
Keep both side trays and the central crossing open until the green, pink, and orange routes are ready.

Board notes 5 details

Layout: The board has left and right side trays, a yellow vertical box marked 2, green and blue Ls marked 4, a purple bar marked 2, red and teal bars marked 1, a pink square marked 4, a white vertical box marked 1, and an orange square marked 4.
Goal: Drain the center-right single-capacity pieces and upper blue/yellow routes before sending the large lower footprints toward the side trays.
Opening: Start with the blue L and yellow vertical route, then clear purple, red, teal, and white before moving the green, pink, and orange side-feed pieces.
Danger Zone: The side trays can add cats while the center is occupied. The white and yellow vertical boxes need their arrow-aligned columns, and the green L shares the lower-left route with the pink square.
Mechanics: Two external side feeds, arrow-marked vertical boxes, and staged capacity depletion make the central crossing order-sensitive.

Why should the one-capacity boxes move first in Level 39?
They occupy the central slots needed by the larger side-feed pieces, so clearing them preserves the middle for the later route.
How do the side trays affect the solution?
They are live entrances that can add cats during the run; leave their approach lanes open until the large lower boxes are ready.