Game Overview:
The two oracle games, released at the same time, were the third and fourth installments to the Game Boy lineup. Both games took place on far off islands, and were another break from the traditional save-the-princess. (Seasons took place on Holodrum and Ages on Labrynna.) The games came with a special password system, a first for the Zelda series. When you beat both of the games, you recieved a special password that you could enter into the other game. You would then start out the game with a sword, a shield, and four heart containers instead of three, and the game featured a very special different ending.

Just like Oracle of Seasons, tons of new things and ideas were introduced. Here is the same thing I wrote for OoS, just tailored for Oracle of Ages:

In Oracle of Ages, many new ideas, items, and people were introduced to the Zelda series, and many of which has never returned. Some of the new characters included Ricky the Kangaroo, which was a kangaroo that helped transport Link over Holodrum, Moosh, a large blue bear that allowed Link to fly for a short time, and Dimitri, a goron-like creature that helps Link swim in deep waters. The game also features Nayru in human form. The game was also the only game to feature the Subrosians, a race of people living in an underground lava deposit. There was also a new item, called the Harp of Ages, which allowed Link to control the ages (past, present, and future) of Labrynna. Another new idea was the introduction of rings. Over time, Link gathered different rings that contained different powers, which helped Link along his journey. But by far the greatest of the new things were the Gasha Seeds and Gasha Nuts that followed them. Gasha Seeds, which were given to Link throughout his journey, were able to be planted in soft earth. The seeds grew into trees that produced Gasha Nuts, which contained hearts, rupees, rings, or even heart pieces.

Both games were rather alike, featuring the same types of puzzles and challenges, but overall, each game was unique in its own little way. So each game is definately worth a play.