Hey @Outpost_31,
your idea of grouping items together and then using the group as collision is very clever!
Right now, the collision block does not support collisions for group items.
group items are actual items in the 3D world. Your block currently checks if the group item (which has no collision volume on its own) is collided against, but your intention is checking for collision of one element within the group item.
I’ll be in touch with the developers so that this can be made possible. We did not stumble upon this way of using group items ourselves, so your intent here is really enlightening to us 
As an alternative I offer you the following alternative to the collision issue while we improve the block:
We use the when item collides with anotherItem block and turn the item whenever it collides with something that is not the camera or the snake head. This is how the code looks:
Here’s how it looks like in action:
Here’s how you can make use of the AND - block to check if two conditions are true. I also named the snake-head ‘medusaHead’ and added it to CoBlocks.
(There’s an update of CoSpaces next Monday that will add amazing improvements to CoBlocks. It’ll make these expression blocks way easier to build, too!)
I wrote you a PM with a link to the updated space. You can remix it to use the code yourself if you want
Hope this cleared things up!