First there was Pac-Man, and it was good. The video game generation had finally found its mascot, and no one thought life could get any better. Then there was Ms. Pac-Man, and players wondered how we got along with only one maze and stationary bonus items for so long. Finally there was Jr. Pac-Man and gamers were simply blown away...
Jr. Pac-Man was the natural sequel to Pac-Man and Ms. Pac-Man (I hope she's Mrs. Pac-Man now), and as such expanded on the classic Pac-Man formula. Jr. Pac-Man adds several new enhancements so it's no coincidence that most people consider Jr. Pac-Man to be the ultimate Pac-Man game.
The first and most obvious enhancement is the scrolling maze. Now mazes can fill several screens which leads to new patterns and strategies. However since there is no radar in Jr. Pac-Man, players need to remember which parts of the maze they've already cleared. Thankfully the 5200 handles this scrolling beautifully with no jerky motions.
The next major enhancement was the addition of giant dots. Giant dots are actually made from normal dots after they come in contact with a bonus prize. While the giant dots are worth more points than regular dots, they slow Jr. down and make him more vulnerable to the roaming ghost monsters. It's best to stop the bonus prize before it makes too many giant dots or Jr. may find he doesn't have the necessary speed to outrun a purusing ghost.
The last enhancement is the most deadly. Now roaming prizes destroy power pellets when they come in contact with them! There's nothing like running towards a power pellet with a gang of ghost monsters in hot pursuit only to see it destroyed moments before you reach it. It's best to grab prizes before they move too far or you may regret it later.
Although conversions of Pac-Man and Ms. Pac-Man for the 5200 were decent but nothing extraordinary, Jr. Pac-Man really shines on the 5200. The only thing missing from this version are the intermissions between levels, which were probably cut due to space considerations. There is also at least one major bug still in the game which causes power pellets to remain on screen if the player dies while a prize is destroying it. If this happens the game must be reset as the power pellet cannot be eaten. However this bug is rarely encountered and usually doesn't interfere with the game.
Jr. Pac-Man was actually developed for all three of Atari's systems (2600, 400/800, and 5200), but only the 2600 version made it out and only after being delayed for 3 years. Like most prototypes from 1984, Jr. Pac-Man was canceled due to the Tramiel take over and the collapsing video game market. So Jr. Pac-Man will remain one of the best kept secrets of the prototype world.