Along the "collectable.patch" file I added a "data" folder which contains the images of the key. Just throw it in you "meandmyshadow" directory.
To add the key block just use the Level Editor.
UPDATED:
- Fixed the key count reset on play record.
Modified the key and added 3 different versions of it (for some option). The keys were modified by "ctdabomb".
Added another patch to the rar file which is attached to this post, it is the same except it makes the player to pick up the key automatically.