SNES Tetris Strategy

Thread in 'Strategy' started by Josh Tolles, 27 Jul 2014.

  1. I have been wanting to share some of my thoughts and experiences on this game. This is not going to be scientific at all, so take the things I say with a grain of salt. Basically, this is what works for me. Since a lot of people don't like some of the quirks of this game, I thought I would share my philosophy on how to handle some of the things it does, how I manage to enjoy this bastard of a game.

    I will add to and edit this as time goes on, but let's go ahead and get started.

    1. Level 9 is your playground.
    My least favorite thing about this game is you have to start on Level 9. It can be boring, and it makes for a loooooooooong game. And to add insult to injury, this game is actually pretty easy from a speed standpoint all the way up to Level 29. I mean, Level 19-28 is moderately difficult, but not much more than NES's Level 18. But now I am straying off topic, so back to the point:

    To get the most out of your playing experience, you are going to want to score 250-300k on Level 9. This is totally do-able. Basically, try to get as many Tetrises in a row as you can. If you don't get at least 4 or 5 consecutive to start, just quit and try again. Trust me on this. If you are not getting easy Tetrises, its not worth wasting your time. The weird thing about this game is tends to get "stuck" quite a bit. It can get "stuck" in easy-Tetris mode just as easily as it will get stuck in hard-Tetris mode.

    Another thing to keep in mind is that with those ten frames of pre-gravity, you can get away with some crazy, crazy stuff. So have fun. Push the limits to try to keep your consecutive Tetrises going. This is important, because you don't want to get bored or complacent. Level 9 is the time to be brave and have fun, don't waste it.

    Also, it is important to get those extra 50k on these easy levels. (I say "extra" 50k in regards to this way of thinking: generally, we are shooting for about 200k every 100 lines, which sets us up with about 600k going into Level 29.) It is imortant to get out in front to start things off, because, as I mentioned, the game can get "stuck" in "difficult" mode. You are going to go through a stretch of 50 lines or so where you do not get many Tetrises. There is no science behind that statement, but it happens to me in almost every game I play.

    This game can feel easy at times, and it can feel like a brain-buster at times. Which leads me to....

    2. This game is all about feel.
    Trust your feelings on this game. If you start a game, and the Tetrises aren't just dropping in your lap, don't blame yourself. Quit and try again. Some games feel good, some don't. Don't waste your time on the ones that aren't nice to you. There are easy games waiting to be played.

    Also, if you think you feel a drought coming on, you are already in a drought. The instant you feel like the game is getting stingy on longbars, knock your whole damn stack down. That is the only way to snap the game out of its stinginess. If you think a drought has begun, it definitely has begun. Trust your feelings.

    The same goes for a flood. If you get two pieces in a row, always expect a flood of four or five or maybe even something crazy like 8 or 9 out of 11. Even if you get two, and the third piece is something different: that is a trick. You stack those two things on top of each other, I can guarantee that the fourth piece will be the same as the first two. If you feel like a flood might be coming, do something, anything, even if it is drastic and ridiculous, to keep yourself from making a stack.

    Now, there is a good thing about floods: even longbars can flood. So you are going to want to keep a three-high Tetris well going to capitalize on the longbar floods, but always keep your feelers open to the possibility of disaster, and when you do feel disaster coming, act immediately.

    3. Levels 19-28 are easy.
    These levels will seem difficult after the snail crawl you took to get here, but that is an illusion. Levels 19-28 are pretty much just as easy as Level 18 on NES, so go for Tetris! I expect to score 200k or more on these ten levels.

    Just remember to trust your feelings, though. I claim that these levels are as easy as NES's 18, but that is only in regards to speed. Remember that this game will flip into droughts and floods before you even know what has happened. So if you were cautious on the earlier levels, keeping your feelers open to sudden changes, be doubly or triply cautious on these faster levels.

    Here is a picture showing you which blocks you can clear with auto-shift active (DAS charged), comparing NES Level 18 to SNES Levels 19-28. The top line shows which blocks you can clear off a wall charge (instant shifting), and the bottom red line shows which blocks you can clear if you require a full six frames before the first shift.

    4. Levels 29-31 are totally playable.
    The reason Levels 29-31 are playable is because this game gives you ten frames of pre-gravity before your piece starts falling. For a good DAS charger, ten extra frames are more than enough to get those pieces all the way to the side, and so you should be totally at peace on these levels. Furthermore, if you are good at "going low", then you are good to go: line out on to infinity. Personally, I try to go for Tetrises, but I have a lot of respect for the limitations of getting pieces to the left side.

    Also very important to keep in mind is that this game allows diagonal-downs. You can move the pieces left and right whilst soft-dropping. Which means that "accidental downs" sometimes occur. Pressing down on Levels 29-31 kills your pre-gravity. There is no doubt about it: these levels are intense, which means you are going to be pressing your buttons harder than normal, which could lead you into trouble with accidental-downs. My advice is to sort of favor the "up" button rather than the "down" button. Just keep your thumb away from there and you shouldn't have to worry about it.

    5. Levels 29-31 are totally playable....Or are they?
    While these levels are playable, the rules of DAS charge don't seem to always hold up. I cannot explain it. I have torn apart the ROM, watched things move frame by frame, but I cannot find an explanation for the following:

    It is very, very hard to get longbars and inverted J's all the way to the left. I can wall charge half way down the playing field on the right side, which should give me full charge, and still the next longbar or J won't reach the left side over a two-block-tall wall. The only way I know for sure that those pieces will make it is I must have a full charge, plus get a line. I can't explain this. I don't even want to anymore. I just know that is the name of the game, the only way to go about it. Getting a line shouldn't have anything to do with charging DAS, but it works.

    I am not saying that you won't get a longbar or a J all the way over there without a line. It works about 2/3 of the time. But if you clear a line plus have a full DAS charge, it will make it almost 100% of the time.

    Obviously, the simplest explanation is probably correct: if the piece doesn't make it, I simply did not have a full DAS charge. Okay. So I screwed up. But I am telling you that I know I have the charge to get it there, but it simply doesn't. Or at least it cetainly seems that way. So, get a line if at all possible, trust me.

    6. This version of Tetris loves to play the "opposite game."
    This is sort of a mix of droughts/floods combined with the feel aspect I mentioned earlier. Didn't know where to put it, and it really deserves its own category anyway.

    Basically, if you need a J-piece, you are probably going to get a lot of L's. If you need an L, you are probably going to get a lot of J's. Ditto for Z's and S's. If you don't have a two-wide spot, you are probably going to get a lot of squares. Just be prepared for this. If you find yourself in need of a J, assume it won't come and figure out a way to get around it immediately.

    But the door swings both ways. You can also use this behavior to your advantage. If you find yourself in one of those situations in which you must leave yourself needing either a J or an L, go with whichever one the game seems to be giving you in abundance at the time. Or the other way of thinking about it is, if you have noticed that you are not getting any J's, avoid getting into situations where you need one, avoid it like the plague (this will also bring about a longbar drought, too, so keep that in mind; if you need a J and are in the middle a J drought, the longbar could save you...but it won't...guess what, you are now in a combined J and longbar drought, oops).

    That is all I can think of right now. I am sure there is a bit more to it than this. But here is what you need to take away:

    *Score big on Level 9.
    *There will be multiple droughts.
    *There will be floods of every kind.
    *Levels 19-28 are actually pretty easy.
    *Levels 29-31 are playable, but the game won't let you get that piece all the way to the left side because it hates you.
    *Avoid accidental-downs on Levels 29-31.
    *You will always get the opposite piece of what you need.
    Last edited: 28 Jul 2014
  2. One thing to consider is that pre-gravity is 10 (or was it 11 when you add spawn?) frames. Unlike an evenly divisible 12 which would cleanly allow for two whole shifts before the piece begins falling, you "lose" 1~2 frames of DAS relative to gravity every time a piece enters the playfield. So you're constantly in a cycle somewhere between positive edge (16 DAS) down to negative edge (10 DAS). Unless you constantly wall tech to top it off at positive edge, "full DAS" is fuzzy.

    I suppose it may also be possible that the line clear animation invokes a different code path in spawning a new piece that gives an extra frame of control before gravity starts or something. If you can show some test cases, this could bear further investigation.
  3. I am curious about how much pre-gravity there actually is, and I hope you can shed some light on it. I say 10 frames simply based upon the programming regarding this, which reads something like "ADC 0A". I don't recall exactly how it reads but I do know it is $0A that is added to the amount of frames before drop.

    I recall you saying that there are 11 frames of pre-gravity, I just don't understand where the extra frame comes from.

    I checked this out pretty thoroughly one day, and I found nothing which proved that clearing a line had any effect on DAS or pre-gravity, but again, I am now thoroughly confused as to where these extra phantom frames are coming from. If there is a frame or two of control during spawn, that would explain some things.

    Edit: I have just made a "map" of the path of the longbar on Levels 29-31, and if I did my math correctly, I can clear a three-high wall on the left with ten frames of pre-gravity. I am pretty sure I have cleared 4-high walls before. I will have to play around with Level 31 and see if I can clear a five high wall off a line clear and full charge.
    Last edited: 28 Jul 2014
  4. The value of pre-gravity in the debug menu is 10, but I believe the piece is visible for an additional frame when it spawns. What I can't remember is if you have active control on that frame. The other possibility is that the piece is visible for 12 but pre-gravity for only 11, but it has been a while since I checked.

    Anyway, "off-by-ones" are common in programming depending on how/when you check something. I recall the DAS repeat rate (or some other value, but I'll assume it was that for this example) being set at 5 by default in the debug menu, which works out to moving every 6th frame just as in NES. Setting it to 0 meant moving every frame. It's possible that the semantics of pre-gravity are similar -- 1-10 might be ten counts, but 0-10 would be eleven counts in that case.

    Anyway, I'm foggy on the whole thing and will have to frame step it again myself. :p If you have any observations that point one way or another on my half-recollection, let me know. :D
  5. Awesome and informative - love it :wub:

    - Jono
  6. Great strategy guide, Josh. Hopefully the last guy playing SNES gets to read it, I think his name is Josh? Haha! I keed, I keed.

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