As said in the Philips Odyssey 2001 page, the Odyssey 2100 was released in 1978. It is an improved version of the 2001 which used the National Semiconductor MM-57186N chip. It plays six different types of games, each type having several variations, making a total of 23 games:
Odyssey 2100 games and reset functions operate exactly like the 2001. Its closest US equivalent is the unreleased Magnavox Odyssey 5000, which played 24 games for up to four players. Games included Tank Battle and Helicopter, which Odyssey 2100 did not feature because of its different game chip.
To see the user manual of the 2100, click the pictures to see them in original size.