Blender Game render: Broken model

[Babyforce]

Hello community. I began to make mods for a game but I encountered an issue. The model seems to be fine just by looking at it (I had to fix few things but nothing serious) and even looks great on a Blender Render:

However, there is a huge problem in the Blender Game render:

Before spending a lot of time on making a mod with it, I’d like to know if the render actually shows what any game would actually display and if there is a way to fix this. Flipping the direction of normals just worsened my case. I also recalculated the normals but nothing changed and the UV Map seems to be good:

I got the model from here http://www.models-resource.com/pc_computer/hyperdimensionneptuniarebirth1/model/10984/
I opened the .dae file (The FBX has way too many bones and the rendering shows a black model).

Thanks in advance.

[Razorblade]

The problem is caused by an incorrect mesh, which might be a result of previous export to dea, or import to blender.
Its often the case that during conversions things get wrong like this.

select your object, edit mode, under mesh verticles remove doubles (think you could keep default value) after that recalculate normals.
it will be fixed then, if you still see some strange stuff repeat remove doubles but then with an altered value.
in your case some triangle vaces are double or not connected stuff like that,

after your ready you might perform a tris to quads, btw nice model