Immaterial and Missing Power/Mixup
IaMP is a game that has no throws, with the exception of one of Youmu's special moves. Because of this, it is a common misconception that the game lacks in mixup options. The classic trio of fighting game mixup is patterned after rock-paper-scissors -- that is, there are three tactics you can use, each one defeating the other.
Rock - Attack Paper - Block Scissors - Throw Where Attack (Rock) beats Throw (Scissors), Throw (Scissors) beats Block (Paper), and Block (Paper) beats Attack (Rock).
To this end, the basic mixup of IaMP can be considered as follows:
Movement Bullet Melee Where Movement beats Bullet, Bullets beat Melee, and Melee beats Movement.
If you further extrapolate the various types of attacks in the game, you have permutations of the above:
Grazing (Movement) Graze Attacks (Movement) Bullets (Bullet) Bullet-type Attacks (Bullet) Physical-type Attacks (Melee) Guard Crush (Melee) Blocking (Normal) Blocking (Auto/Air)
You can see that in this layout there are two types of attacks, Physical and Bullet. Not all attacks that are projectiles are bullet-type, and not all attacks that are melee are physical-type. For example, Remilia's Spear the Gungnir is an attack where she throws a spear of energy; however, the attack cannot be grazed like a bullet, essentially rendering it a physical-type attack. Similarly, Sakuya's Soul Sculpture fills the screen with slashes, but all of them can be grazed; in essence, the move is a full-screen bullet-type attack. The permutations grow more complex when you factor graze attacks and guard crushes into play, because certain graze attacks are capable of beating certain melee attacks and guard crushes can beat movement and blocking.
There are also two types of block in this game: "normal" blocking, which is what happens when you block an attack correctly according to its high-low status, and "auto" blocking, which is what happens when you block incorrectly (autoblocking is depicted by a red flash during your block animation).
During normal blocking, you sustain no spirit damage from normal moves, minor spirit damage from bullets, and, depending on the special, chip and/or spirit damage from specials and supers. While autoblocking will not affect bullet-type moves, specials, or supers, it comes into play against melee attacks. Autoblocking (as well as airblocking) a melee attack will cause spirit damage just like a bullet attack, and after a certain point your spirit bar will be depleted; also, guard crushes instantly deplete your spirit bar if autoblocked.
The possible permutations of what happens when you put particular attacks against other ones is beyond the scope of this page and is something largely learned through matchup experience. However, beyond this basic level of mixup is another layer in how strategy works in this game.
IaMP is a game based on the Touhou series of danmaku shmups, where your mobility options are gradually decreased by patterns of incoming bullets in the game; finding the "answer" or "a way out" is frequently the point of the exercise. This is replicated in IaMP where every character has the ability to launch an attack string in which there are decreasingly fewer means of escape. Highly skilled players not only have the ability to attack with the fewest gaps but are fully aware of what escape routes an attack string has and can utilize countermeasures to punish these attempts.
To illustrate this in a real match situation, let's consider Reimu vs. Yuyuko. Reimu's primary strength is the ability to cover large areas of the screen with bullets at relatively low cost, allowing her to do it constantly and relentlessly, punishing her opponents when they try to move around the pindown. Let's assume that Reimu has placed Yuyuko in the corner and has got her blocking.
- 8D high jump up. This will carry her up to the top of the screen, where she has initiative over Reimu.
- 6D graze. Yuyuko will graze Reimu's 2C, but not come out with an attack, which is potentially risky.
- 66B graze attack. This will carry Yuyuko grazing through and over the 2C to CH Reimu.
- Get hit.
Obviously, the last two options give Reimu the initiative, as she is free to continue as she pleases, so we'll disregard them. As you can see, Yuyuko really only has three escape options in two directions: forward, and up.
Reimu, however, has counters to both of these escapes.
- HJC9 j.B j.B. Off a 2C, Reimu can HJC9 j.B immediately. Due to the speed of j.B, this will solidly CH all attempts to jump out of the corner and wallslam for further damage. If the opponent does not immediately graze through 2C, they will be in blockstun by the time Reimu's second j.B comes down on them; however, a forward graze attack will leave Reimu in the corner and her opponent out of it.
- HJC9 j.A. Reimu can HJC9 j.A immediately, which will keep the enemy from doing anything due to the speed at which j.A comes out. If the opponent is standing, they will be locked down by j.A blockstun for Reimu to further pressure; however, this option whiffs if the opponent crouches the j.A.
- HJC7 j.2C. Reimu retreats after 2C, covering the area below her with bullets before moving back in either with another j.2C or a j.A (possibly both). If the opponent tries a graze attack, they will more than likely not reach Reimu and be hit out of it; however, because Reimu is not throwing any melee attacks they are free to 8D up out of Reimu's vertical range.
Option 1 counters Yuyuko's upwards escape; options 2 and 3 both have the potential to counter Yuyuko's forward escapes. As you can see, though, each one of the counter-escapes only covers one possible path, and anticipating incorrectly allows the opponent to get out free. Guessing correctly, however, allows Reimu to net damage (something she sorely is lacking in) and continue the pressure.
There are many situations in which this type of mixup is applicable, and every character in IaMP is capable of this kind of mixup to some degree. For more information on metagame and reading your opponent you can refer to David Sirlin's excellent article on Yomi layer 3. For information on IaMP-specific mixups and situations, read Xenozip.'s IaMP blog.