Algodoo

Somewhat capable worm that can at least cross the small blocky hill.
To walk to the right, following the sequence D-LEFT-A-RIGHT can work. D-RIGHT-A-LEFT will carry you to the left.
If upside-down, follow the controls the other way around, doing the leftward sequence to go right and vice versa.
The worm now has grippy ends to allow for different walking behaviors.