Gradius IV Fukkatsu (グラディウスIV～復活～, lit. "Gradius IV: Revival") is the fourth arcade installment in a series of scrolling shooter video games developed by Konami Computer Entertainment Tokyo. It was preceded by Gradius III, released in 1989, although other non-numbered spinoffs had been released such as Gradius Gaiden. This title brings a considerable graphical upgrade, particularly with the use of colored lighting. In addition, there have been several additions and removals to the vaulted weapons system; specifically, the edit mode has been removed and an online ranking system was added.
The core gameplay of Gradius IV remains relatively unchanged. However, several changes were made on the weapons system in the transition from Gradius III. First of all, the edit mode has been completely eliminated, as are the "Snake Option" (s.option), the "Reduce" shield type, and the seventh powerup category. The seventh powerup category was the one that was labeled "!" and would produce detrimental results, such as reducing the speed or eliminating the weapons of the ship.
Source: Wikipedia, "Gradius IV Fukkatsu", available under the CC-BY-SA License.