I recently bought terraria a few days ago but i'm struggling to launch it on my Linux (Ubuntu 16.04, was 14.04) when I downloaded the game. After looking at my files I've noticed one of my files is titled 'unconfirmed.' I'm wondering if it has not downloaded properly and is the reason I can't launch it. Some please help me fix this.

Here is a screenshot of the file

After downloading the game, you should only have 1 file and that is the first one on your screenshot.
Then right click on it -> Properties -> Permissions and check the box that says Allow executing file as program.
After that you can install the game via Terminal.
I didnot have any issues downloading or installing the game, and I am using Ubuntu 16.04

Yes, the download seems corrupt or incomplete. Download it again, the file name of the current version is gog_terraria_2.12.0.15.sh
The others in your folder are older versions.

I have followed both suggestions and I now have the normal update file but I still can't launch terraria whenever I try to launch it through the terminal it doesn't work and through the desktop shortcut it doesn't seem to respond or even give an error message.