How do I prevent the player from reversing direction?

Hello all,

I've been working on a "slug" to be controlled with the tile movement behavior. I have two issues that I can't figure out how to resolve.

The big one is the player can reverse direction simply by pressing the opposite movement key. I'd like to prevent this so that the player has to do an actual 180 degree turn similar to snake or centipede movement.

The second issue I'm having is the ability to press more than one movement key at once. This creates some odd visuals as the turning animations play when the player isn't turning. Is there any way to stop this?

dropbox.com/s/flp0h238tjtj9dq/blockslug.c3p

I made quite a few changes, but the code is much simpler now:

dropbox.com/s/786liwkysb7mh7i/blockslug2.c3p

Thankyou very much! It works perfectly and the code is indeed a lot more tidy.

Here's a code based way to do the animation as well.

dropbox.com/s/45sc1227zvak0vb/wormMove1.c3p

dropbox.com/s/2ejripn5sja4rtj/wormMove2.c3p