So, you are moving from one version of the game to the other, and you want your custom levels / settings. Moving saves over is very simple, you just need to know a bit about how the file structure works.
Go into the root folder of where you keep the free game. It should look like this, click on the internal folder.
2. Now, you will see 3 folders in here. Saves is what you are after. You can either choose to copy this entire folder over, or just specific things from it.
3. The file names are pretty self explanatory as to what they each save, so I won't detail it here.
4. Find the location in Steam where to copy the files. In your steam library, right click on the game Mazified, hover over "Manage", and click "Browse local files".
5. This opens the same folder structure as before, but in Steam's game install directory.
6. Simply copy over what you want to save from one version to the other.
Exact same process, just copy from Steam install folder to your other game copy instead.