[One, Two, Middlesboogie]

I'm afraid there is no invincibility cheat for AO, whether for PC or PSX. AE is the only one of the two Abe games to have such a thing.

I found that door hard, but now I quite like it.

As soon as you enter, run to your right (you must run or you'll get eaten), then run/roll through the tunnel, into the next screen, then do a running jump onto a ledge that you'll see near the right wall.

Stand under the meat sack and jump up to drop some meat down to the Paramite. This will make the other two Paramites in the screen to the left come running. Wait until they've eaten it, then drop another piece. Run back to the screen on the left and chant briefly to open the Abe portal. Run quickly back to the right and up onto the ledge with the meat sack.

Then, tell a Mud to follow you. Drop meat to the Paramites, then run back to the screen on the left. Tell the Mud to wait. Run back to the meat sack ledge.

Repeat for the other two Muds.

When all three Muds are waiting by the bird portal, get back to your safe ledge, and drop one last piece of meat. Run back left, and stand next to the Abe portal as you chant to free the other three Muds.
As soon as you free them, boulders come down near the Abe portal, and if you're not on the left-hand side of them, it'll be nearly impossible to get past them, and the Paramites will eat you. If you're as close as possible to the Abe portal when you free the other three, then you needn't worry about dodging the boulders, and you have the added bonus of the Paramites getting squished if they try to come and get you.