Do you have this game stored with Github? If not, you can just edit the game that @shakao posted, change the name, and continue from there. The idea is, you can add extra tilemaps to the variable ‘tilemaps’.
I noticed in the forever loop, that you had set an animation for ‘blob’, but it didn’t have any frames (frames is just an array of images). So I just made the blob, ‘blob up and down’. : -) Also for the bird (beast), I created an array of images called (beastImagesRight, as the image is facing right), loop through them, create a clone (copy), flip the image horizontally, and then finally add that to beastImagesRight. All of these images are in the gallery. That way you can use the character animation extension to have the bird fly left and right.
To keep the speed of the enemies simple, and the code you had already made for the ‘touching’ wall events, I added a variable 'enemySpeed, and used that in the different places. If you want to have the enemies move at different speeds, you could create a new enemy ‘Kind’ and create a new speed for that kind, or you could use the ‘sprite data’ extension to save a random speed per enemy. I do this in my game ‘Shark Frenzy’ and even change the animation speed based on the sprite speed. (Shark Frenzy)
I like your game so much I changed the code that Shannon had posted. Here it is: