Since you are planning to have more types of slimes, there are two ways to do this:
1. add them as different animations to the same "slime" sprite,
2. or add new sprites (slime2, slime3 etc.) and combine them into "Slimes" family.
One sprite with multiple animations may be easier, but if you want them to be different objects, go with the family.
Use instance variables, I believe variables xMove, yMove, xDirection, yDirection, way should be instance variables, as they will be unique for each slime instance.
If you decide to use the family, you should do these changes while the project is still small (this will save you a lot of time in the future):
Move all instance variables and behaviors from the slime1 sprite to the family level.
Change all your events to work with the Slimes family.
So your function could look something like this:
On Function "Compare"
For each Slimes
...Set Slimes.xMove ...