I'm trying to use this Gunstructor and for some reason, I can't use it. Everytime I try, Unity just crashes. I have tried this on google chrome, firefox and internet explorer each to no avail. I'm almost positive I have installed the unity player right.

What version of the Unity Player did you download? You are using a PC and not a Mac right? I had a similar issue when I upgraded to version 5 by accident.

It won't work in Chrome worth a damn. use it in Firefox. Unity keeps making changes to the flash player then Gunstruction has to adjust to the changes. What you want to do is install version 4.5.4

Gunstruction has been working on moving to version 5 and that's what you probably installed.

Here's the link for earlier version of Unity - choose the 4X tab

http://unity3d.com/get-unity/download/archive

I'm getting a screen that says error launching unity player, with an option to "show error details" that says failed to create unity loader, and the other option is "install manually" which takes me to unity to download it. I do that and everything goes ok, it says it was successful but I get the same screen when I go back to gunstruction. Happened out of nowhere. Any ideas?

I'm pretty sure my problem was that I was still using 10.6 for my Mac and Unity 5.0 requires 10.7 or newer. I downloaded to 10.10 and it works like before. So if you have a Mac and are still using 10.6 I would suggest updating to 10.10. It's free in the app store.