Some Memes

I like the distinction I made in Some Memes for Oni, between factual and imperative memes. I don't like the name “imperative”, though, so here I'm going to replace it with “strategic”.

Anyway, the idea is, there are some memes that provide facts about the game, and others that provide strategies for dealing with it. Sometimes a fact will imply a strategy—for example, the fact that pulsars turn around at the start of the endgame suggests that you should keep an eye on the pulsars—but that doesn't happen all the time. There are facts that don't imply strategies, and there are strategies that aren't implied by any particular fact.

For Tempest, I wanted to separate the facts from the strategies, and that's what I've done. The facts are in the previous two essays, and the strategies are here.

Another thing to be aware of is that all strategies are not created equal. Some, I think, are absolutely essential, while others are just interesting hypotheses. Of course most of them are recommended to some degree, or I wouldn't bother mentioning them; I'll try to make clear which ones are just ideas.

Old Ideas

Here are some ideas I developed back when I used to play Tempest as a real arcade game.

• When you're shooting a tanker, you can rock back and forth to fire down the adjacent panels as well, and that will kill the tanker and its contents all at once.
• On levels where flippers use the “weave” pattern, you don't even need to do that—the flippers will return to the original panel, so you can just wait and shoot them then.
• On circular levels, there's another symmetrical thing you can do. When a tanker reaches the top, if you can get to the point exactly opposite, the flippers will reach you at the same time, and you can kill them both at once.
• Flippers at the top aren't necessarily a problem. If you can engage them one or two at a time, you're fine, it's easy to kill them once you get used to the timing, but if you get a whole bunch coming at you at once, you may be in trouble. What you want to do in such cases is fire continuously, but then the fact that you have a finite number of shots becomes a problem. The solution is to move to a panel with a long spike. The spike will absorb your shots and let you reuse them, so you can fire continuously for longer than normal.
• On the star levels (N = 13) and maybe a few others, the tankers approach much faster than the flippers. So, if you want to kill everything before it reaches the top, you should crack open the tankers as soon as possible.

Black and Green

The ideas in the remaining sections (except for the last) are ones I developed more recently, while trying to figure out how to deal with the black and green levels. They apply to earlier levels, too, but aren't really necessary there.

Timing

Most of the interesting stuff about timing comes from pulsars.

• On the earlier levels, I got in the habit of acting exactly once between pulses. I'd have a base, a safe area, where I'd sit, and between pulses I'd hop out and back, firing, in one direction or another. On black and green, however, there's not always enough time to get out and back. So, one thing I like to do is find a small, temporary safe area nearby, and swing across to it as one action, then swing back as the next.
• Although I can rarely do it, I often think that one action is just not enough, that I need to act twice between pulses, so that the rhythm is a waltz rather than a two-step. Of course, then there's even less time available, so the actions have to be even smaller. Probably instead of whole firing patterns, they need to be very specific—kill this flipper at the top, fire the shot that will kill that pulsar.
• In addition to multiple actions, you can also have multiple purposes to a single action, as in other games, notably go. That sounds good, but is hard to do in practice. The only time I really do it, that I know of, is when I fire to kill a flipper at the top and then use that as the start of a firing pattern.
• Everything I said above is true, but it all misses the point. The thing about my habit that I needed to unlearn wasn't the “exactly once”, it was the “between pulses”. You need to be able to act even during pulses. If you're planning to kill a fuseball, it doesn't matter whether the pulsars are pulsing, just go do it! You should still be aware of the pulsing, but you should only respond to it when you're attacking a pulsar, or moving past one.
• If you can really get into the style of play where you act during the pulses, the game has a very different sound. I've never been able to use that to get back to the same style, though.

Not everything is about pulsars, though.

• When you first start killing flippers at the top, you need to watch to make sure you get the timing right. But, once you get used to it, you don't need to watch after all—you can gauge how fast a flipper is moving, and how far away it is, and just fire at the right time, with the whole thing taking place in your peripheral vision.
• Speaking of peripheral vision, just as you want to keep your eyes on the vanishing point when looking ahead in driving, I sometimes think you ought to keep your eyes on the vanishing point of the board, and just take in all the action indirectly.
• If you want to kill a fuseball that's at the top, you wait for it to go back down, then hop over and shoot it, right? Not necessarily. On the higher levels, between the time it takes the signals to wind through your brain and the time it takes you to hop over to where you want to be, the fuseball may already be halfway across the panel, if not already on the way back up. So, you need to get used to the timing of things, and start moving while the fuseball is still at the top, so that you arrive just after it starts going down.

  Of course, if the endgame starts right then, the fuseball won't go back down after all, and you'll run into it and die. But, that reminds me of a rule I used to use when I was skiing: if you're not falling down, you're not pushing yourself enough.

Control

• Another bad habit I picked up on the earlier levels is firing a complete burst when killing a flipper at the top, just to be safe, instead of firing only a shot or two. Don't do that—it is important to keep some shots in reserve.
• Get used to making small, controlled movements. If you're in an area with long spikes, and can't move away, and there's a pulsar down at the bottom, you should be able to hop back and forth avoiding it while firing to wear down the spikes. Similarly, if you're on a jagged level (say, N = 3, 9, or 13), and there are flippers coming at you from both directions, you should be able to hop back and forth on a point to get favorable curvature against all of them.
• Faster is not always better. For example, in that firing pattern I described above, where you swing across then swing back, you might as well use all the available time to move. In fact, if you move at the right speed, you're more likely to get a shot on every panel.

Linear vs. Circular

• When I play on a linear level, I establish a base near one edge or the other, and stay there. In the old days, the base would be just a few panels, maybe a quarter of the board, but now I think it should be more, maybe about half. (Also, now I tend to use the right edge instead of the left.)

  Having a base is a good approach when non-chaser fuseballs are present. You may have to kill a few of them at first, but eventually they'll all end up on the other side of the board, out of the way, doing their random walk.

• The idea of having a base has a counter-meme, which is that you shouldn't try to hold a fixed territory. That's easy to believe for circular levels, but true even for linear ones. If you are absolutely committed to staying in your base, with all enemies to your left (or right), you can be forced to the edge and killed. Instead, you need to be flexible, able to leave your base and come back later.
• There's another idea that is closely related, which is that you should watch and fight on two fronts. Again, that's easy to believe for circular levels, but true even for linear ones.

Now, here's a whole strategy that works only on circular levels. I don't use it all the time, because it's hard to set up, but if you can set it up, it works well.

• The fundamental concept behind of the strategy is that it's not a good idea to stay as far from the enemies as possible. Fuseballs and pulsars like to move toward you, so if you move far away, half will go one way around the circle, half the other, and you'll have enemies all over the place. If, however, you let the enemies get close, escape only at the last second, and then stay close to them, they'll stay bunched up, all moving the same way, leaving the rest of the board open for you.
• Sometimes you can improve the bunching after the fact, by hopping into the middle of the bunch and then back out, all between two pulses.
• You can also improve the bunching before the fact, by eliminating isolated fuseballs and pulsars. This is a good idea even if you aren't trying to use the whole strategy, since it creates nice open spaces.
• In any case, once the enemies are bunched up, you just lead them around the board. If you like, you can pick off the leading units; in fact, sometimes you have to, if the bunch is starting to get spread out. A better plan, though, is to go after the spikers. They are mostly harmless, and easy to kill; and since a lot of the board is open, you can jump out and kill them almost anywhere, as long as you remember to return quickly afterward.
• Going after spikers is a good idea even on linear levels. You have to kill the fuseballs and pulsars that come into your base, of course, but in your free time you can run around killing spikers. In fact, if you want, you can run around firing at random. If your base is half the board, and you cover it with random fire, in theory you can kill half the spikers as they emerge. In practice, though, the spikers fire too, and the shots collide and cancel out.

Instant Death

• The one thing I find frustrating about Tempest is that on the black and green levels, there are certain events that are almost indistinguishable from random, unavoidable, instant death. Almost. Once you get used to the levels, you realize the events aren't random, and can be avoided, but they're still instant death, and are no fun.

  So what are these events? There are two kinds, both involving a dot emerging right underneath you. If it emerges as a fuseball, it can rush up to the top and kill you before you can react; and if it emerges as a pulsar, it can pulse before you even realize it's there.

• What makes the events avoidable is that you can see where the dots have stuck to the surface and are ready to emerge. If you're really good, you might be able to see exactly which panels the dots are on, or even keep track of the order in which they appeared. I can't do that; the best I can do is see which parts of the board have the most dots, and avoid those parts.
• You can also avoid instant death by using conservation of units. Once conservation is in force, if you kill things in moderation, the dots will emerge at the same moderate rate, and maybe you'll have a better chance of responding fast enough.
• Here's another possibility, using partial conservation of types. (I'm not entirely sure this is a good idea, but I do think about it a lot.) If you kill a fuseball, the next dot will probably emerge as a fuseball, which is dangerous. So, if you avoid killing fuseballs, there's less danger. You can apply the same logic to pulsars, in which case you end up doing what I talked about above, going after spikers.

All of that leads me to a general rule that I sometimes follow.

• Let all the enemies emerge and settle down before you start attacking. This serves several purposes. It helps you avoid instant death, both because it ties into the rule about moderation, above, and because not killing things leaves you free to focus on staying away from emerging dots. It lets you see the whole pattern of how the enemies are arranged, so that you can find the best way to obtain open space (by eliminating isolated fuseballs and pulsars, as above). And, finally, it gives you time to get used to the pulsar rhythm.

Now, here are a few more thoughts.

• Shooting a tanker is a lot like having a dot (or two) emerge underneath you. It's not random or unavoidable, but it can still lead to instant death if it's a fuseball or pulsar tanker—that's why it's important to be able to tell the different kinds apart. (Actually, the death can be random, sometimes, when you accidentally shoot a tanker that's just emerged.)
• So, if you're going to shoot a tanker, hit it and run, so that you're not right above it when it hatches. For fuseball tankers, by the way, the definition of “above” is surprisingly large. The fuseballs can appear on the outer grid line of the adjacent panel, and can move outward when they get to the top, so they can kill you anywhere within a five-panel area.
• A lot of the time, it's convenient to let tankers hatch at the top. For pulsar tankers, it's easy to swing across and kill the newly-hatched pulsars before they get down among the spikes, if any. For fuseballs tankers, it's not quite as easy—you can't swing across until the fuseballs move off the top, and then they can move as far down as they want before moving horizontally and becoming vulnerable. So, if there are spikes, they'll probably get away, but if there aren't, you can kill them easily.

Miscellaneous Tactics

• When there are flippers at the top, don't just sit in one spot and wait for them. That isn't an efficient use of time. Instead, move right up next to them and fire, to kill them quickly.
• I suspect that fuseballs come to the top more often when you're nearby. So, if you're trying to kill a group of them, and there's always one at the top getting in your way, you might move away and see if that helps.
• Once in a while you'll run into a synchronized fuseball-pulsar pair: two units moving along together, with the pulsar pulsing whenever the fuseball isn't at the top. There's not much you can do against such a formation. The best approach, I think, is to be patient (and maybe move away, as above). Sooner or later the fuseball will move the wrong way, or stay down when it's supposed to come up, and then you can get in and kill them both. If you're on a linear level, though, and trapped at the edge … well, probably you lose. The best approach in that case is to make a run for it (that is, be flexible and leave your base).
• You don't need to be directly above a unit to be able to kill it. For one thing, as the game speeds up, shots move relatively more slowly, so that a unit may move into the path of a shot after you've fired it; for another, the unit doesn't even need to be fully in the path—when a unit is flipping between panels, it can be killed by a shot on either one. Firing on an adjacent panel is particularly useful for killing pulsars.

Stupid Tricks

Finally, when I was gathering information for the previous essay, I discovered a couple of stupid tricks you can do.

• If you're on one of the early yellow levels, and you selectively kill off the flippers, you can often get to a state where the only things on the board are fuseballs and pulsars. Then, things are relatively calm. The pulsars don't fire, so everything is nice and quiet except for the pulsing, and if you can get the pulsars to bunch up (see above) and avoid running into the fuseballs, you can keep the game going almost indefinitely.

  You can do the same thing on higher levels, but it doesn't work quite as well. Once you get to Y11, there are spikers again, and they fire at you and make it harder to get down to just fuseballs and pulsars; and once you get to C12, the pulsars fire at you too.

• Then, if you do the same thing on a level like Y9, where the number of pulsar flips per pulse is exactly 2, and you're persistent in making the pulsars bunch up, you can get them all onto the same panel, and get a parity effect. The pulsars move together, and move twice between pulses, so there's parity—a set of even panels where they can pulse, and a set of odd panels where they can't. So, all you have to do is sit on an odd panel, and you're safe—the pulsars will come sit underneath you, flipping back and forth between two panels and always pulsing on the other one.

  When you're trying to make the pulsars bunch up, you'll run into a parity problem—dividing the panels into even and odd, as before, you'll find that some pulsars pulse on the even panels, and some on the odd. Fortunately, there is parity violation. If you move past a pulsar at the right moment, you can get it to change direction in mid-flip. That can change odd pulsars into even ones, and also smooth out any other timing differences.