Minecraft Java Edition – How to Power Multiple Upward-Facing Pistons

If you watch at about 2:50, you can see most of the left half of the circuit. The part for the stairs looks like it isn't shown very well but that is less important timing wise. Watch carefully over and over and see if you can replicate it this way. It looks like the repeaters for the middle activate and deactivate immediately. So the order (from a circuit standpoint) for both directions is M, L+R. This works for closing because the middle repeaters don't have anything to activate until the blocks are pushed into the middle. When opening, they will retract the middle immediately.

Breaking it down:

Opening

1. Middle repeaters deactivate (middle pistons retract)
2. Delay
3. Left and Right redstones deactivate (left and right pistons retract)

Closing

1. Middle repeaters activate (nothing happens because the middle pistons are not in position)
2. Delay
3. Left and Right redstones activate (left and right pistons extend)
4. Now the middle pistons have been pushed into position and are activated by the middle repeaters

The words compact and Redstone don't usually go together :) There could be something simpler than this, probably using some weird combination of water, pistons, and chewing gum, but this is the best I can come up with: a basic delay circuit (from the wiki):

In the screenshot, there is actually a pressure plate on the right, bit hard to see. I prefer not to use buttons, when running for my life. :)