You have to separate the images and the script in your mind. So you can more powerfully combine the AGD. An image can behave in different ways (scripts) and a script can adopt different images. Another important thing is to decide what has animation (cost in sprites) and what does not. I would do like this: 1 player sprite: sprite 0 (script player) image 0, frames 3 right. image 1, frames 3 left. image 2, frames 3 death. (when LET imege = 2 dies)
1 end level door sprite object 1 closed door (16 × 16) changes to object 2 open door when you have all the keys.
5 items to collect sprites 5 objects, don't spites. you can make them blink by changing colours. detectobject method helper to you.
3 kill player on contact sprites. fixed in player script.
2 moving and animated enemy sprites. The rest of sprites animated statics and enemy killers at your disposal.