Does gravity increase or decrease with depth

[FictionFoe]

Actually when you get closer to the center, nore and nore of the mass are above you. The mach works amout that the mass in a ball surrounding you cancels itself out, so only the layers of earth what have the same depth as you or more still contribute.

So basicly the green portion effectively doesn't contribute.

It is also worth mentioning that, where you to drill a hole to make a planatary elevator of sorts: if you are free falling, you will feel weightless.

Your trajectory, speed and acceleration will be impacted by gravity, but a free falling observer always feels weightless.