Sonic the Hedgehog
The Sega Genesis had "add-on" systems that incorporated "Sonic" games. "Sonic CD", released for the Sega CD, was a 2D platform game released in 1993. The game introduced the characters Amy Rose and Metal Sonic and featured levels that differed depending upon whether Sonic was in the past, present, or future time frames. "Knuckles' Chaotix", a spin-off released in 1995 for the Sega 32X, featured Knuckles and a new group named Chaotix fighting against Dr. Robotnik. The game featured a two-player cooperative system in which the on-screen characters were connected by magic rings. There was also "Sonic Eraser", a puzzle game released exclusively on Sega Game Toshokan in 1991.
Dreamcast
Released in 1988, the Sega Genesis (known as the Sega Mega Drive in Japan, Europe and Brazil) was Sega's entry into the fourth generation of video game consoles. Selling 30.75 million units worldwide, the Genesis was the most successful console Sega ever released. The successor to the Genesis, the Sega Saturn, was released in Japan in 1994. The Saturn was a CD-ROM-based console that displayed both 2D and 3D computer graphics, but its complex dual-CPU architecture made it more difficult to program for than its chief competitor, the Sony PlayStation. Although the Saturn debuted before the PlayStation in both Japan and the United States, its surprise U.S. launch—which came four months earlier than originally scheduled—was marred by a lack of distribution, which remained a continuing problem for the system. Moreover, Sega's early release was undermined by Sony's simultaneous announcement that the PlayStation would retail for US$299—compared to the Saturn's initial price of $399. Nintendo's long delay in releasing a competing 3D console and the damage done to Sega's reputation by poorly supported add-ons for the Genesis (particularly the Sega 32X) allowed Sony to establish a foothold in the market. The PlayStation was immediately successful in the U.S., in part due to a massive advertising campaign and strong third-party support engendered by Sony's excellent development tools and liberal $10 licensing fee. Sony's success was further aided by a price war in which Sega lowered the price of the Saturn from $399 to $299 and then from $299 to $199 in order to match the price of the PlayStation–even though Saturn hardware was more expensive to manufacture and the PlayStation enjoyed a larger software library. Losses on the Saturn hardware contributed to Sega's financial problems, which saw the company's revenue decline between 1992 and 1995 as part of an industry-wide slowdown. Furthermore, Sega's focus on the Saturn over the Genesis prevented it from fully capitalizing on the continued strength of the 16-bit market.