I'm probably wrong on more than one point, but...
Overkill is the damage you do to an enemy after you have depleted its health. It is initiated by Assault (i.e., homing lasers), Blade, or Raid. Getting Overkill creates a Combo Bonus, which causes a multiplier to be applied to the value of enemies shot down, as well as perhaps to other things, like jewel value (I'm not sure). The Combo Bonus can be maintained by chaining enemies; the chain health is indicated by the thin green bar in the upper-left. When setting a Combo Bonus, doing Overkill damage on more than one enemy (which I think has to be medium-sized or larger) results in a Multikill multiplier being applied to the Combo Bonus.
You can combine your shot/laser, Assault, and Blade/Raid to get a very high Combo Bonus. For example, against the red enemy near the beginning of Area 1 (the one that appears with a "Warning" label), laser it until it has about 25% health left and use Assault to finish it off. You'll have a few frames before it explodes where you can use Blade and laser on it some more. You should be able to get a Combo Bonus of 25-60,000. You can chain it all the way to the yellow crystal, where you should repeat the same procedure, except that you'll finish it off with Raid for a Combo Bonus of around 60,000+. Both your Delayed and Ethereal Shifts should become available by this point if they haven't already.
The key thing about the Combo Bonus is that
when setting a new Combo Bonus, a fraction of the old one is added to the new one. This allows you to build a very high Combo Bonus throughout the stage and boss. It provides incentive to purposefully let your Combo Bonus chain expire at certain points in the stage. It's really hard to maintain your chain anyway. Only medium and large enemies seem to refill the chaining bar, so it's probably not possible to chain entire stages.
For reasons which I don't quite yet understand, it's important to trigger Delayed Shift or Ethereal Shift when you have a Combo Bonus active. During a Shift, the Combo Bonus is frozen so you don't need to chain, and you cannot perform Overkill. When a Delayed or Ethereal Shift ends, so does your Combo Bonus.
Delayed Shift needs to be played like Espgaluda where you allow enemies to flood the screen with bullets before you shoot them down. The density of bullets increases when Delayed Shift is active. It is the primary method of acquiring jewels, which I believe are score items. The more you collect, the more valuable they become, I think; they change color, up to white/diamond. Their value might be affected by other factors, such as Combo Bonus. Delayed Shift can be activated when the Delayed Shift bar (fat blue bar at the upper-left) reaches 50%. It fills on its own, but I believe doing Overkill damage helps it fill a bit faster. Finally, Delayed Shift increases the power of your weaponry; this can be stacked with Overdrive (press and hold Bomb to activate).
Collecting jewels during a Delayed Shift fills the Counter Shift bar, which is the thin pink bar underneath the Delayed Shift bar. There are three levels of Counter Shift. The level of Counter Shift simply determines the radius of the aura that emits from your character when Delayed Shift ends. Bullets that this aura touches are converted into jewels. It also does some damage to enemies; it can effectively kill popcorn enemies and larger ones as well if they have been damaged beforehand. You can manually use a Counter Shift to prematurely end your Delayed Shift. The advantage of this is that it allows you to clear the screen of bullets while leaving enemies alive on the screen that you can immediately use to set up a new Combo Bonus. It can obviously be used defensively as well.
Ethereal Shift is the primary method of collecting coins, which increase the Multiplier counter in the upper-left corner. The Multiplier is applied to most sources of score in the game, with the exception of the End Stage bonus, and I think Timer bonuses during bosses. Ethereal Shift can be activated when the thin orange bar in the bottom-left reaches 50%. It fills on its own and I don't think anything can cause it to fill faster, but I'm not sure. During an Ethereal Shift, more enemies are spawned, allowing you to acquire more coins. If you get hit during an Ethereal Shift, you will lose a bomb; you will die if you have none left. There is nothing you can do to safely and manually end an Ethereal Shift. Also, you cannot use Raid during an Ethereal Shift, but you can use Blade as much as you like; your Assault is set to rapid-fire Auto-Assault as well (double tap Assault button to toggle this when not in Ethereal Shift, but it won't be as fast).
Ethereal Shift is also necessary to enter Counter Burst Mode. This is a special mode which triggers when you finish off a segment of a boss's lifebar during an Ethereal Shift. You hear a siren, the screen background turns red, and the intensity of the boss's current bullet pattern increases several-fold. During Counter Burst Mode, you can continue attacking the boss for a massive increase to your Combo Bonus when it ends. Counter Burst Mode lasts for the duration of the Ethereal Shift, so it's important to activate Ethereal Shift when a section of a boss's lifebar has a sliver of health left in order to maximize the amount of time you have with which to do Overkill damage. Getting hit during Counter Burst Mode does not cost a bomb or life, but it ends the Ethereal Shift prematurely.
Essentially, Type-S scoring boils down to setting a high Combo Bonus through Overkill when possible, and maintaining a balance between Delayed Shift and Ethereal Shift usage. You need to collect large amounts of both coins and jewels, so you can't just use one type of Shift throughout the whole game. There are some areas of the game that are better suited for Delayed Shift and vice versa; for example, the rush of enemies just before the Area 3 boss is perfect for an Ethereal Shift, in my opinion. It's helpful to watch TRIS-GRAM play his own game a few times: youtu.be/z2ZcE45Z_ec. Note that coins no longer change color when playing Type-S in version 1.00 or higher, and also that the Multiplier counter is visible. The main point of mystery is that we have multiple components (coins, jewels, Combo Bonus, etc) that we need to make use of to score well, but we (or at least I) don't understand how they affect each other and the formula that the numbers go through
en route to your score total.
I don't know a damn thing about Type-C play.
When playing Easy and Normal Mode, you lose a bomb whenever you get hit. This is not the case in Normal-Ex to Pandemonium.
Rule Mode provides a preset character. The level and accessories are fixed. This is useful for score competition because everyone is on equal footing. Story Mode allows you to level your character (up to 50 in the current version) and wear accessories, which modify various parameters. Eventually, I believe TRIS-GRAM will be adding dialogue and such to Story Mode, but plans can always change.
Extra accessories are unlockable by completing achievements ("Medals") during the game, which add points toward your Class Level. I suspect that you get a new accessory whenever you raise your Class Level, but I'm not sure. Check the Certification section under Game Data. Class Level 2 gave me a Black Candle, while Class Level 3 gave me me an Ethereal Diffuser+. I think. I'm actually not sure when I got those accessories, but this seems to make sense.
Takoshi, on 05 January 2012 - 10:21 PM, said:
I have a more basic question: I've been acquiring coins at the end of each play I do, but only the coins that I have collected for that stage. Is there any way I can collect the coins I gathered from the stages before that? For instance, let's say I get 4000 coins on stage 1, and then I get 3000 coins on stage 2 and for some reason, die. I will get the 3000 coins from stage 2, not the 7000 I have collected this play. Is that normal?
Yeah, I think it's normal for the number of jewels and coins you come away with to be throttled somehow. Otherwise you could buy out both of the shops pretty quickly.