First Look at the Game Boy
Details about Nintendo's new handheld machine were finally given early in 1989, as the GameBoy was set for an April 21 release that year. Set to sell alongside the GB were 4 titles: Super Mario Land, Alleyway, Yakuman, and Baseball.
The only thing of note in this release is the early announcement of F-1 Race. Although the game was probably well into development at this time, it didn't see a release until November 1990, probably since the game needed some kind of gimmick (4-player adaptor) to actually be worth selling.
Some early pictures from Nintendo's Game Boy ad campaign: