By Kitten
Chikyu Kaiho Gun ZAS

(JP December 18, 1992)

Obscure outside of the realm of serious collectors, ZAS is what is quite possibly the most technically impressive game in the entire Game Boy library… Which is doubly impressive when you bother to consider that it was the first and last game the team working on it would ever put out for the console. Produced by a relatively little known company by the name of T&E Soft, it hit shelves not long after Trip World and unfortunately didn’t happen to fare any better.

By the time that late 92 had swung around, output for Nintendo’s famous device was already slowly declining in quality, and publishers had begun to fall back on easy solutions to bring in bigger profits. Quality entries like this were disappearing, and they were being replaced by floods of incredibly lazy and/or incomplete games, many of which were produced under a well-known license to ensure sales. Though the Game Boy would go without a successor until late 1998, the vast majority of its good games were released in 93 or prior, with only a couple of great titles in 94 and very few outliers beyond that.

Although it’s fairly widely considered that we began to see people grow out of perceiving games as nothing more than a sheer novelty at this time, this mostly applied to home console games. As I mentioned much earlier, people frequently saw the Game Boy largely as an opportunity to play versions of games they already loved on a device they could take anywhere. That, or they had no resources to evaluate the quality of new games and drifted to other familiarities, like games based on cartoons or movies that they or their children were fond of. T&E Soft had no foothold to really advertise their game, and, perhaps unsurprisingly, few people bought it.

The depressing reality of ZAS being relegated to much the same fate as Trip World is hard to bear, especially being a fan of the space shooter genre that it belongs to and as someone who so loves the hardware it was released on. What makes it impressive is a number of things I’ll be going over, but what it does best, above all of its many interesting facets, is that it controls and plays incredibly well in motion.

A relatively little-known fact is that the Game Boy, as a piece of hardware, was actually more powerful than the NES. Although we saw many late-life NES games do what the Game Boy never could, this was because additional hardware was added to the cartridges to make them more capable (companies like Konami and Sunsoft even had proprietary chips that could add extra sound channels). Though you couldn’t enhance a Game Boy game in the same capacity due to the restrictive size of the carts, you could get more out of a game without needing a fancy chip to do so.

ZAS was one of very few games to actually show what Game Boy hardware was capable of, and it did so with incredible finesse. Capable of rendering an absolutely remarkable number of enemies and projectiles on the screen at once, it was genuinely a sight to behold, and it managed to do this with only the occasional bout of slowing down. It plays remarkably smoothly for a Game Boy game that happens to have so much going on, and that’s intensely valuable to its mechanical design on a fundamental level.

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The quality of its visuals are in some ways entirely unsurpassed by its peers, and the most notable way in which it distinguishes itself is made obvious shortly after beginning your game. On the very first level, ZAS treads territory that few Game Boy games dared to by featuring a transparent foreground layer in addition to the background layer. Then, taking it a jaw-dropping step further than that, it had them scroll independantly of each other (what is referred to as parallax scrolling).

How this is possible is a bit tricky, and very clever. To start, let’s explain what “flickering” is. Older hardware has strict limitations on how many sprites can be on the screen at once, and where those sprites can be. When those limits are exceeded, the hardware will attempt to resolve this by automatically choosing whatever things are most taxing and rapidly alternating what frames they are displayed on. The result are sprites that appear to the naked eye to be flickering on the screen, and it’s something so common you’ve almost undoubtedly seen it in many, many games.

A technique called multiplexing allowed designers to take the matter into their own hands and designate certain sprites to automatically be rotating which frames they’re visible on. This was most typically done with projectiles fired from weapons, as they could very easily fill a screen and tax the game. For example, have you ever wondered why the bullets in Contra for the NES are always kinda fuzzy looking? Multiplexing. It’s one reason why it runs so smoothly despite its impressive action, and how it can get away with a weapon like the spread shot not crashing the game.

Observing how flicker works on the Game Boy leads to something particularly interesting. Because of the Game Boy’s cheap LCD screen, it was victim to something that is referred to as ghosting, which is what occurs when an LCD screen is being relayed information at a rate faster than it can display it. This results in the picture briefly lingering on the screen before being updated, and together with what I’ve already explained, this means that when flickering quickly enough, sprites on the Game Boy’s screen would appear to stay visually consistent. Although they’d appear uniquely faded – as if differently shaded than everything else – the “flicker” would appear nonexistent (something that modern emulators can imitate with a particular option).

A few designers realized this, and then tried to take advantage of it. Gradius: The Interstellar Assault, for example, used it to keep its options from being too visually distracting (and from taxing the game). Trip World used it to make sprites that were underwater visually distinct from what they’d look like above water. Castlevania II: Belmont’s Revenge used it in one level to make mountains in the background seem as if they were further off in the distance. And ZAS? Well, the way ZAS uses it takes it far beyond what others attempted.

Many designers saw the LCD screen as a tremendous hurdle to action games, but T&E Soft saw it as an opportunity. The Game Boy can’t do genuine parallax (though there techniques that imitate it), it can’t do transparency, and it can’t render more than one background/foreground layer at once. So how does the first stage in ZAS appear to do all these all things? Multiplexing on an LCD screen. What looks like all of these effects going on is actually just the game taking turns drawing two separate backgrounds on different frames, and then scrolling them at different rates.

Instead of succumbing to compromising the quality of their design and building themselves around the limitations, they worked with them. There is literally not one other game (to my knowledge) within the entire library of the Game Boy that does exactly what ZAS does, and it was released more than 5 years before the Game Boy would become obsolete to the next iteration of hardware. It doesn’t stop with its incredible command of the hardware on the first stage, either, and does amazing things in subsequent stages that I could still go on about.

All this impressive technical wizardry would of course fail to really matter if the game didn’t look gorgeous, but it absolutely does. Beyond the cleverness of its technical feats and smooth display, ZAS is also lovingly rendered with luscious sprite work and some incredible animation. Basic enemies are often given multiple frames of animation, and level detail is incredibly carefully rendered to create detailed environments that never get in the way of being able to decipher what is going on. Every boss enemy tends to surprise in multiple ways as well, with the just the first transforming from a simple sphere into a massive battleship.

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Exceeding expectations hardly ends with the visual work, as the music’s exceptional quality cannot be understated, either. Compositions are varied and complex, but never need to borrow from the channel that the game’s effects are playing on (a common problem with complex music on old hardware). Music from the first stage sets the tone for a memorable, light-hearted adventure, while the track for the stage’s boss is frightening and hectic, as if the realization of the weight of your journey has struck you with a terrible anxiety.

As the game continues, the second level’s music lightens things up a bit, but the shocking encounter you just survived feels as if it’s set a distinct tone of apprehension for what comes next. Each level features a unique music track, as does each end-of-stage boss. The lack of repeated tracks helps establish a sense of progression rarely seen in other games of the era, and the attention given by the sound designers to ensuring that ZAS distinguishes itself from lesser games is immediately apparent.

When considering it on a mechanical level, ZAS is everything you could ask for out of a game on the system. Where T&E’s space shooter series for the MSX, Laydock, borrowed from games like Xevious, ZAS is much more reminiscent of more recent games like Gradius, Aleste, and especially R-Type. Similarly paced to each of those titles, you find yourself on a journey through five slowly-scrolling, different levels before reaching the end.

Each level features distinct enemies, visuals, gimmicks, sub-bosses, and bosses. The variety and abundance of these elements is almost unbelievable given the hardware limitations and obscurity of the title, and their carefully spaced usage make each level have a remarkably powerful identity. While ZAS imitates a vast array of other shooters with a high frequency, it never really outright steals from them and has its own unique twist on everything. Beyond just homaging light elements exclusively from well-known shooters, the scope often extends beyond that. Stage 2, for example, has several bits that feel as if they pay tribute to Quarth, a game that only tangentially belongs in the same genre.

Everything is executed to near-perfection, leaving the game to impress you with its mechanics on far more than just the status of its delightful variety. In terms of difficulty, it hits somewhere between R-Type’s constant tension and Gradius’ flow of disarming ease between serious moments of frenetic challenge. The tools to cruise your way through the game are there in front of you, but it ultimately comes down to execution and proves itself to be the most enticingly made shooter on the console without competition. A hard difficulty is there to push the game even further past both its limits and yours, with bullets now frequently filling the screen and the game requiring greater aptitude and strategy to conquer.

T&E Soft’s incredible grasp of both space shooters as a genre and the Game Boy as a piece of hardware are something that put almost all other designers for the console to shame, and yet this was the only game they’d ever grace the thing with. On the one hand, it’s easy to be consumed by how disappointing it is that this title wasn’t successful and we couldn’t have seen more like it, but on the other, we’re kind of lucky to have gotten it, at all.

I frequently see people lament that ZAS wasn’t released on a more capable console, but let’s consider here that great art defines its medium as much as that medium defines its art. ZAS is an excellent title specifically because of its medium, the climate it was released in, and the determination of its designers, and it would be an inherently different game were it to have been made for something else. The Game Boy didn’t hold it back, it defined it and allowed it to be precisely the beautiful thing that it is.

The root of appreciation for all things comes heavily down to context, and ZAS demonstrates mastery of its own. There is a sincere artistry in the way it defies its trappings, and it encapsulates a time when boundaries meant something significant to game design. To constantly look at games as “held back” is to never truly appreciate what they did, and to fail to appreciate what came before is to realize that everything we hold dear will merely be made obsolete by the notion of progress.