I've made some small improvements to your code and:
- Edited Origin of player sprite so the player base is at the feet of the player sprite (since it should be the players actual position on the ground in case you walk into solid objects)
- Added a stone as a solid object editing it's collision polygons. So you're colliding with the stone with your feet location properly
The "trigger once" will be important as soon as you've added an animation to the character. Otherwise the animation will restart every tick (so you will think the animation will not work but it's actually just restarting the animation about 60 times per second)
I recommend to download the Z-Sorter plugin from Rex.
Using this plugin allows you to automatically change the z-order of your player sprite (or anything else that's moving) based on their Y position on the layout.
So right now in the example i've sent you you will notice that it looks correct if you walk BEHIND the Stone.
But as soon as you walk in front of it your character will still be behind the rock.
Using Z-Sorter plugin will help you to get this properly done <img src="{SMILIES_PATH}/icon_e_wink.gif" alt=";)" title="Wink">
http://c2rexplugins.weebly.com/rex_zsorter.html
Personal tip:
In case some animations are visually exactly the same (for example walking left or right).
Do not create another animation for it... this will only steal resources which isn't required.
You could simply MIRROR the animation instead using an event.