The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From Banzai Labs:
Artillery Launcher plays huge, high-quality real explosion sounds from artillery, explosives and other high power weapons. It's a fun, entertaining app with everything from artillery sounds to nuclear explosions. The app was designed to be simple and easy to use with the ability to rapidly fire off a sound, scroll and fire another one, so quickly that you can overlay sounds to create awesome battlefield effects. Sounds include: - 3 inch Gun - 90mm Cannon - Anti-Tank Missle - 152 mm Howitzer - Dynamite Blast - Cannon Firing - Cluster Bomb - Hand Grenade Explosion - RPG - Exploding Window - Exploding Building - Nuclear Blast - Heavy Artillery - Triple Volley Cannon - Tank Obliteration - 80mm Mortar More weapons being added all the time!