User:1ccsDontMatter/Dodging strategy

Normally in shmups, one wants to avoid danger in the forms of bullets, enemies, and obstacles when aiming for a goal such as a 1cc, 2-all, or score run. Dodging theory is an analysis of the different types of dangers one is likely to face as well as axioms for coming up with solutions to such obstacles.

= Avoiding bullets =

Routing
In general, the best way to avoid any type of danger, including bullets, is to know what will happen beforehand and to plan a safe route to avoid that danger. Even randomized elements of a shmup can benefit from routing by analyzing the random elements and routing towards the greatest probability for success. For instance, routing oneself into a safer, less bullet-dense part of the screen far away from the source of random danger.

Threat zones
Sources of danger, such as enemy ships, enemy cannons, or fired bullets, can be thought of as projecting a threat zone along whatever their path is. The closer one is to this zone, the greater the chance the player will make an error and collide with a bullet. It follows then that dodging strategies should be centered around controlling and minimizing threat zones, thus giving the player the largest areas of safety and freedom possible. Analysis of threat zones is one way to theorize about the safest possible solution for any bullet pattern. In practice, they are mostly helpful for blind play or pre-routed play where the best strategy for any situation is not yet known or needs to be developed firsthand. Visualization of threat zones will lead to faster development of safe routes or improvements on old strategies.

Speedkilling
A vital strategy in many shmups, killing enemies as quickly as possible usually denies the existence of threats entirely. There can be no errors without threats.

Streaming
One of the most common ways to minimize threat zones is to force sources of danger to overlap each other via streaming. Essentially, threats that are overlapping share the same threat zone, and by luring many sources of danger into a small area or controlled trajectory, the player effectively frees up some other part of the screen they can use for maneuvers.

Herding / Luring
When possible, lure threats/bullets off screen or into areas that are already polluted with threats. It's much better to have one polluted area and one clear area rather than two mildly polluted areas.

= Bullet patterns = Because "reading" bullet patterns is often error prone, and in extreme cases, impossible, it's useful to learn strategies that can be used to avoid danger without relying merely on sight. If a bullet pattern falls into a known type, a known solution is likely to be effective in surviving it.

Static bullet patterns
Static bullet patterns are the same each time, so their threat zones fill predetermined positions and timings regardless of the player's position or other game states. Static patterns cannot be herded or lured, but instead they are very predictable, and thus static patterns are often solved safely by memorizing safe spots. Static patterns are more common in older shmups as their predictable nature makes them relatively simple to conquer with enough analysis.

Threat zone
Being completely static, the threat zones of static patterns can be visualized as thin, stationary lines traced from the sources of danger to the edge of the screen. Anywhere between these lines should be safe for maneuvering. In the case that a moving enemy fires a static pattern, one can still visualize the static threat lines and safe spots radiating out from the source.

Aimed bullet patterns
Aimed bullet patterns are patterns that are oriented towards or aimed directly at the player. These are the majority of patterns in shmups.

Aimed even
Also known as enclosing patterns, aimed bullet patterns with an even number of bullets contain two or more streams of bullets aimed away from the player. Usually the best way to survive even patterns is to not move and let the danger pass by. Macro dodging is not recommended as even patterns are usually quite wide and are essentially designed to punish macro movements.

Threat zone
Aimed even patterns can be visualized as fans of threat lines oriented towards and around the player. Depending on the width of the area between the threat lines, it is sometimes possible to micro dodge threats that overlap with an even pattern. If there are no overlapping patterns, it's best to just not move and avoid the threat lines entirely.

Aimed odd
Odd bullet patterns contain one or more streams of bullets that are aimed directly at the player. Usually the best way to survive odds is to tap once perpendicular to the source of the bullets.

Threat zone
Aimed even patterns can be visualized as one or more lines oriented directly at and piercing the player's ship. By far the most common type of pattern in shmups. Macro dodging aimed odd patterns can be safe if the pattern isn't very wide. Continuous aimed odd patterns (including streams of single bullets) can only be tap dodged for so long until the player runs out of space on screen. Cut backs should be used to create an opening to slip under in order to continue tapping in the opposite direction when out of room.

Random bullet patterns
Random bullet patterns are patterns that may or may not be aimed at the player; they spawn with an unknown trajectory. Often, random patterns are actually oriented in some way towards the player, and are actually aimed random patterns. Random patterns can be bullets with completely random trajectories from a central source, or they can be patterned attacks such as rings that expand with an unknown trajectory that may or may not be aimed at the player.

Threat zone
Random patterns can be visualized as nebulous cones or circles. Since the trajectory of incoming attacks is random, there is no real way to form a consistent strategy against random patterns. Analysis of such attacks may reveal that certain parts of the screen will be less dense than others, increasing the chance of success if taking refuge in that area; however, the need to remain in a certain position to attack an enemy may make such solutions impossible to effectively execute. Ultimately the only way to avoid random patterns is to read the incoming bullets and react.

Homing attacks
Homing attacks are bullets or missiles that spawn with some initial trajectory but continue to curve towards the player for some amount of time. Homing attacks are usually either slow with a high turn rate or fast with a low turn rate.

Fast bullet, low turn rate
Often depicted as homing missiles, the threat zone of this type of attack is a cone in front of the projectile. The sides and especially back of this attack are safe. Exploit their slow turn rate by cutting them off at a sharp angle and getting behind them. It will take a long time for them to reorient towards you and they may time out.

Slow bullet, fast/infinite turn rate
Often depicted as energy balls that follow the player around, outmaneuvering homing attacks with a high or instant turn rate is impossible, so general distance should be sought until they despawn. If possible, lure them all together in one area and then escape to the opposite side of the screen where one can deal with other patterns without worry of the homing attacks interfering.

Magic bullets
Magic bullets (todo: maybe there's another term for this?) are bullets such as rotating bullets (Compile), oscillating bullets, or curving bullets. Depending on their speed and density, it may not be realistic to think of magic bullets as individual bullets with changing trajectories and threat zones. More likely, it may be best to visualize them as large swathes of bullets/fat lasers/large moving circles, and their entire trajectory treated as one large threat zone that should be avoided, as particularly erratic magic bullets with fast oscillations/rotations are often too dangerous to consider trying to weave through.

Aimed random patterns
Aimed patterns with elements of randomness added. They are the majority of bullet patterns in newer shmups. They usually cannot be avoided by memorizing when to tap/not tap like normal aimed bullets and instead must be reacted to.

Static aimed patterns
Combines elements of static and aimed patterns. Very common in all sorts of shmups. One possible strategy is to deliberately wait in the threat zone of the static attack between volleys. This will lure aimed shots to overlap the static pattern, thus leaving some other areas open for maneuvering.

In the example animation, the player deliberately waits in the known path of the static pattern. This lures the aimed shots into overlapping the static pattern, thus reducing the total area of threats on the screen. This leaves the player with two sides completely free of threats. Had the player waited outside of the static threat zone to begin with (as is likely one's first instinct), the aimed shots would have instead filled that safe space. The player would then have to make an extremely dangerous crossing of the static threat zone to avoid the aimed shots.