Yes, and if you see my latest message you can actually use the changed tile set. I updated code already to allow you to upload a sprite sheet to use. Keep the background transparent.
If you can find a blank place on the sprite sheet, you can put a character or two right on the sprite sheet and I can use them.. either for the player or even the bomb enemies, depending on what you make and how you change the sprite sheet. The code that determines if the block is a wall or something you can travel on is based on where the image is on the tile sheet and there are a variety spread all over. Trial and error I guess. Generally anything that looks like a wall is a wall ( water is a wall ) and things like flat (grass) you can walk on.