Adventures on the Moon
The crypt tunnel has some debris on the floor that's fallen out of the walls or ceiling, but while it might make running through the tunnel difficult, it's easy enough to navigate.
Twenty feet in, you see that there once was an stout iron gate that kept would-be looters out, but the moonquake that caused all this destruction has broken the gate. The left section is twisted back against the wall while the right section has completely fallen down.
The actual burial crypts and chambers start after the gate.
Simple crypts are just slots in the wall where the coffin was slid in foot first. A simple plaque was fastened to the end of the coffin, and a fancier marble one was fastened to the outside to seal up the slot.
You can see this because some of the outer plaques have fallen off, smashing onto the floor. Some of the coffins appear to have been pulled out with the desiccated corpse dumped onto the floor.
You also spot several cracks in the sides of the tunnel, from just visible cracks to larger 12" wide. The deeper in you go, though, the bigger the cracks get. Also, the floor of the tunnel seems to be sloping downward.
The fancier crypts begin to appear about 120 feet in. These are larger stone coffins or sarcophagi that have been carved out of the tunnel walls themselves.