In the beginning, video games had no backgrounds. They were drawn over a completely blank screen of a single color (which was black 98% of the time) in order to make the colors of sprites stand out that much more. Some machine makers would actually craft a painted background that made it seem like the sprites were overlaid on a real landscape, like certain Space Invaders cabinets which cast your ship on a lunar base. Barring these instances, games didn't have fancy setpieces or high-quality art to distinguish themselves from each other. They were mostly black screens with bright characters and borders, and they only needed a joystick and a button or two to qualify as a game. It may seem primitive to see such Spartan games, but games that ran on such hardware like Sega's Vic Dual board were among the cutting edge of technology at the turn of the 1980s. What mattered more than how they looked was how they played, and while Sega wasn't anywhere close to the zenith of their popularity yet, they developed some straightforward-yet-entertaining games that were a bit different from all the shooter and maze clones piling on top of each other. One such testament to their innovation was Pulsar. Developed by the folks at Sega-Gremlin in the US, it was all about grabbing colored keys, long before the days of Doom.
Pulsar stands on an odd fence between genres, where it contains elements of your basic Pac-Man style maze game but also has a bit more of a shooting element to it with some shades of Berzerk. You pilot a tank through a seemingly-normal maze with a series of numbered and colored locks in the lower-right corner of the screen. Your goal in each level is to take all the keys around the map and unlock their corresponding doors. You can only hold one key at a time, so you need to move quickly back and forth between the keys and the gates. While it would normally be beneficial to plan the shorter route between all points, that's not quite easy to do when the maze is constantly changing. About every two seconds, one wall retracts right as another conjoined to the same corner extends. Further complicating the ever-morphing maze is a fuel limit which acts as your timer. If you finish with more than enough fuel to spare, you gain a bonus for what you have left, and you get double the points if you unlock all doors in proper ascending order. You can replenish a bit of fuel for each enemy you kill... yep, there are baddies. You didn't think you could pilot a tank in a maze and not get shot at, didja?
There are three distinct enemy types (technically four, more on that in a bit) with which to deal, all color-coded so you can remember which is which. Green enemies dart about randomly, red enemies move in a fixed diagonal bouncing pattern, and yellow enemies smoothly roll along the edges of walls. Yellow ones are arguably easier than less predictable greens and more mobile reds, but they should all be treated as threats as they can all shoot you with fairly fast moving yellow bolts. Interestingly enough, they can't kill you by colliding into your tank, and being really close somehow prevents them from firing. You don't have to kill any of the enemies to beat any given stage, but they often stand in the way and block your path, and destroying them restores a bit of fuel. There's one obstacle in particular which may make navigation around the hallways troublesome, and it's that giant red thing that looks like a nuclear atom. This fourth enemy is the titular Pulsar, and it strangely fires nothing at you but chokes off potential routes simply by existing. Once you shoot the Pulsar several times, you think that would be the end of it, but obliterating it arguably makes matters worse. Its form breaks down and splits into six different enemies of all three types, substantially increasing the danger of roaming around the halls. The unfortunate thing is that it may be impossible to pass the Pulsar and grab a necessary key without nuking it, and it often tends to hang around the northern side of any given map where the keys are invariably found. You can get some good fuel points if you destroy all enemies, provided they don't zap you first.
Pulsar, like most of Sega's early Vic Dual games, never got too popular nor was it remembered once Sega's more popular games came into vogue. Nevertheless, it was one of their more interesting games of the time that offered a lot of challenge, randomization, and more challenge. Seriously, it's not easy, particularly with you only getting two lives instead of the standard three that most other games allowed. Enemies tend to fire fast without much warning, and fuel gets harder to maintain when you need to grab more keys for each successive level. However, Pulsar notably gave more instructions than most other games of the time. When you plop in a credit, you get a screen full of text that explains how the game plays and potential bonuses you can receive. This is a nice touch compared to most other early arcade titles which just dropped you into the action without much information. Pulsar's flyer also shows the game grid and several points of interest as denoted by some bozo named "Fingers" Malloy, back when bogus celebrity endorsements were the norm in gaming. This bit of embarrassing hilarity aside, Pulsar is one of many older Sega games worth checking out to see how they, who would eventually birth Sonic, got their start.