Hey, I took a look at your scene and I could see a few problems.
First of all you need to remove your history, this is probably what makes it blow up in game/previewer. To do this you have to go to Edit > Delete all by type > History (if rigged/animated, you want to take Non-Deformer History). This can be seen in the Channel box.
Secondly you should review your mesh as it misses a lot of splits which will make it next to impossible to do proper animation work. You want to have splits going inside the mesh, if you are unsure how this works I'd recommend to check a modelling and skinning tutorial on YouTube.
Thirdly I saw that you have sorted the meshes in -Z, you want to sort the meshes in +Z as that is how it will be in game.
Hope that it helps!
First of all you need to remove your history, this is probably what makes it blow up in game/previewer. To do this you have to go to Edit > Delete all by type > History (if rigged/animated, you want to take Non-Deformer History). This can be seen in the Channel box.
Secondly you should review your mesh as it misses a lot of splits which will make it next to impossible to do proper animation work. You want to have splits going inside the mesh, if you are unsure how this works I'd recommend to check a modelling and skinning tutorial on YouTube.
Thirdly I saw that you have sorted the meshes in -Z, you want to sort the meshes in +Z as that is how it will be in game.
Hope that it helps!