iOS and Android versions of its first-person zombie shooter The House of the Dead: Overkill - The Lost Reels.
The Ninja Star pack replaces the game's standard Colt gun with an unlimited supply of shuriken, resulting in gameplay that resembles an extended bonus stage from the 1987 Shinobi arcade game. The Vectorman's Ball Gun upgrade, on the other hand, switches out the minigun for Vectorman's lime-green weaponry, and adds Genesis-like particle effects to your zombie massacre.
While Shinobi's protagonist Joe Musashi has made scattered showings in Sega-published games over the years (including a cameo as an unlockable character in 2011's 3DS title Shinobi), these upgrades mark a rare appearance for Vectorman. Fans of Sega's prerendered robotic hero had their hearts broken in 2003 following the cancellation of a planned Vectorman reboot for the PlayStation 2, and the franchise has remained dormant since.
Both items are available for purchase using in-game "Ka$h," which can be earned during gameplay or via microtransactions.