Hey, I made a sliding sokoban-style game! It's in Pulp (not Lua), but have a look if you like.
If you're going to make one of these games, most modern titles I've seen (Snakebird, Stephen's Sausage Roll, Baba is You), have a "move undo" feature, which is almost a necessity for playability. I wrote about how I did this in Pulpscript here: Implementing a time rewind (move undo) system in Pulp