The Atari 5200 was essentially a stripped down Atari 400/800 8-bit computer. The internal hardware was nearly identical, even though the software from the computer version was not compatible with the 5200.
One of the "big" innovations that the 5200 brought to the table was its 360 degree analog joystick. The concept was ahead of its time, and offered an incredible experience for some titles. However, it suffered from a flaw. The joystick did not self center meaning maze games like Pac-Man were a trial of patience. Precision gaming both benefited, but also suffered. Another feature the 5200 offered was the first time a gamer could pause a game.
Even though many critics say that the 5200 was mishandled, the console is a popular collector's item due to the smaller library, and excellent home translation of classic arcade titles.