You are downloading the Doom Shooter XAP file v184.108.40.206 for Windows Phone. Doom Shooter is a free Entertainment App: Using the classic Doom action game as a viewfinder you can shoot anyone around you, heck you can even shoot yourself using the frontfacing. You can now download the offline XAP package file to install & try it.
Download Locations for Doom Shooter 220.127.116.11 XAP file
To try to install it manually from an SD card, you should choose one of the server location above to get the offline Doom Shooter XAP file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.