One of the most famous 'lost' Atari 7800 prototypes, Plutos was known to be in possession of a long time collector but was never released to the public. The reason for this was that the prototype was very unstable and would crash frequently. This was due to the fact that Plutos needed to be run from an Atari 7800 developers kit, and would not run on a stock Atari 7800. However in 2008 the source files for Plutos were found on a hard drive, and due to the efforts of some very talented individuals, the game was patched so it could played on any Atari 7800.
Plutos is a vertically oriented space shooter that plays along the same lines as Raiden. There are six different levels, each with its own unique theme and boss. Not only does Plutos offer simultaneous two player action (selectable with the left difficultly switch), but it has a unique weapons power up system that adds a great deal of variety to the game.
Plutos offers three different types of weapons that can be upgraded up to four times. To upgrade a weapon, you only need pick up a power up capsule of the same weapon you are currently armed with. If you pick up another power up after reaching level four it will wrap around to level one, so be careful!
Plutos has six different levels, each with a boss. However only three of these levels are unique, while the others are merely color palette swaps of the other levels.
This level appears to take place over space station. The level layout and design is somewhat similar to the Hudson shooter Star Soldier, which appeared on the NES and TG-16. The boss of this level is a large generic looking spaceship.
This level appears to take place inside a ruined underground colony of some sort. The boss of this level is an odd looking spaceship with two orbs on the end of it.
This level is the "B" side of level one. While the background is basically, the enemies are somewhat different. The boss of this level is a gold colored version of the first boss. This version is somewhat faster though and takes more hits to destroy.
Ahh a new level! This level has a neat crystal theme going on. Although it might look otherwise, you do not have to avoid the sharp rock peaks sticking out of the walls. The boss of this level is an ugly looking bird shaped spaceship that fires three bullets at you.
Not much to say here. This level is a pallet swap of level 2, but the enemies are more numerous and are much faster. The boss of this level is the odd orb spaceship again.
This is the last level in the game, but it is a pallet swap of level 4. The gray and black colored crystals do make for an interesting background though. The boss of this level is a golden version of the ugly bird shaped ship again, but this time it takes many more hits to destroy.
Plutos is an amazing feat of programming. Not only is it rich in graphics and sound, but the gameplay is tight and measures up quite well against NES and SMS games of the same time period. Plutos shows what the 7800 was capable of if properly programmed. However it appears that few programmers were either willing to put in the effort, or had the skills to get the most out of the 7800. Plutos appears to be complete, but lacks an ending which may point to the fact that there was still more work to be done.
It's a mystery as to why Plutos was never released. Tynesoft was well known developer of Atari 8-bit and ST games in the UK, but was relatively unknown in the US. It appears that they were trying to break into the Atari 7800 market with Plutos and its sister game Sirius (another space themed shooter), but left the game industry before either could be released. It's a shame that Atari didn't pick these games up, as they make a wonderful addition to the Atari 7800 library.