The core game element of many action games ranging from two-player-duel games such as Street Fighter to third person action games such as Ninja Gaiden
is the combat. Although there may be other components like puzzle
solving, much of the game is spent on attacking another player or NPCs.
In some games the impact of these attacks look and feel more powerful
than in others.
In this article I will list observations of techniques used in several actions games including: Ninja Gaiden, Soul Calibur 2, Prince of Persia: Warrior Within (POP:WW), Lord of the Rings: Return of the King (LOTR: ROTK), Devil May Cry 2, Dynasty Warriors, and the classic Street Fighter 2. I will also make remarks based on my development experience on Kingdom Under Fire: The Crusaders (KUF: TC).
As the list of games suggests, this article is mainly about action
games that involve hand-to-hand combat, usually involving swords, and
excludes discussions about the "impact feel" of FPS shooters for the
most part. The techniques involve animations, camera work, special
effects, game controller rumble, and sound effects.
most obvious and most important factor is creating powerful looking
attack animations. A weak motion is not going to look painful no matter
how it is decorated with fancy effects. In this aspect, games that run
at 60 fps have an advantage over games at 30 fps. There are simply more
frames to show the motion in less time, which makes the attack look
speedier. For example in Tecmo' s Ninja Gaiden, the basic
attack is extremely quick and responsive. Figure 1 shows the first
impact occurring on the 7th frame of a 29.97 fps movie clip; equivalent
to 0.23 seconds to strike an enemy.
2 shows about every fourth frame (1, 4, 9, 13, 17, 21, 25, 29, and 33)
of the full basic combo. The second impact occurs on the 16 th frame
and the third impact on the 29th frame. That' s three impacts in less
than one second.
For 30 fps games such as Phantagram' s Kingdom Under Fire: The Crusaders,
it is hard to tell exactly what the attack motion is for impacts
occurring in less than 8 frames. Individual frames become too
disjointed (Figure 3). Additionally, in a 30 fps situation, a
consecutive impact in less than about 5 frames does not look like
separate impact, but rather one long impact. However multiple
consecutive impacts 2 to 4 frames apart are distinguishable with the
help of other effects discussed below. Still with lower frame rates
there are limitations to creating fast attacks. So high frame rates
allow quicker first and consecutive attacks, which in turns reduces
limitations in creating good animation for better impact feel.
Figure 3 . Lucretia is a fast character but her attack animations have a speed limit.
While Ninja Gaiden's
attacks are fast, the heavier weapons in the game such as the "
Dibilharo " in Figure 4 still feel heavy to wield. The heavy sword is
indeed slower for the first two motions, but attack times accelerate
for the next three impacts. The five combo impacts occur on frames 11,
27, 38, 46, and 54 of a 29.97 fps movie clip. This impact schedule
makes the heavy sword useless against quick enemies that strike fast,
but powerful against larger foes that require much beating to defeat.
So heavy weapons can be fast and still appear heavy by making the
latter combo attacks fast. Other techniques described in following
sections also allow for quicker heavy attacks.
Figure 4. The monstrous ' Dibilharo ' sword
a player hits an enemy a certain way, the player expects the enemy to
behave a certain way. Painful damage motions are just as necessary as
good attack motions in creating impact feel. The ideal damage motions
are ones specifically tailored to particular attacks. Fighting games
such as Namco' s Soul Caliber 2, with only two characters on
screen have the capacity for getting pretty close to this ideal
situation. In Figure 5, a stab on the foot causes a limping damage
motion. A grab move folds the opponent in half and stakes him through
the sword (Figure 6).
For other action games, such as EA' s Lord of the Rings: Return of the King,
with many enemy characters and many varying player characters, it is
difficult to create the exact damage response for each unique attack.
For RTS hybrid games, such as KUF: TC, where all those
characters could be in one level, fitting such variety of animation
data in memory is difficult as well. However, by categorizing the
attacks by direction and power, matching damage motions can be used to
somewhat cover this limitation. Figure 7 shows generic yet, effectively
categorized damage motions caused by Aragorn and Gandalf in LOTR: ROTK.
aspect of damage motions is matching the attacker ' s distance and
direction to the target. If the two are not correctly placed relative
to each other, the attack appears to be skewing the target and thus
seem weaker than they could be. There are many ways to approach this
issue. Some games use target locking and automatically align the player
to the target. Others adjust the attacker ' s position slightly to
match the distance. To avoid the problem some games mainly use
horizontal swing attacks that do not require the player to be exactly
aligned to the target.
every attack action, there must be a damage or defend reaction. If the
player hits an enemy and there is no response then the game will feel
less responsive and attacks feel empty. In Soul Caliber 2 after
a round is over, the winner is given a short period to continue hitting
the opponent. If the opponent did not respond to the attacks at that
point, the game would seem a lot less natural. This unfortunately
happens in with KUF:TC due to a bug that shipped, where dying
enemies do not get hit further. An exception to this case would be the
large red dinosaur-like creatures in Ninja Gaiden that ignore
player attacks when they have taken some beating in order to counter
attack (Figure 8). Without this mechanism, the slow creatures would
never get a chance to attack the fast main character. However, even in
this case, the large particles and sound effects give feedback to the
player of the damage inflicted. In games where enemies dissolve, fade,
or explode into pieces, this can be less of a problem.
Figure 8 After taking some hits, the red dragon is about to bite the ninja' s head.
In Capcom' s 2D fighting game Street Fighter, impacts are emphasized by freezing the game for a few frames. In Capcom' s Devil May Cry 2,
Lucia' s attack impact freezes the attacker' s and target' s animation
for a couple of frames, allowing the players to see for sure what
caused the damage. In KUF:TC, impacts caused by smaller blades
and quick attacks cause the attacker' s animation to freeze
momentarily. For heavier weapons, it seemed more appropriate for the
attack swing to run through continuously than get stuck by impact of
the enemy armor.
Frame freezing gives a moment for a player to see the attack motion which may be rather quick to see otherwise (for Lucia in Devil May Cry 2)
and also creates a feeling of resistance caused by the impact. To make
the impact feel more powerful, it is better for the freeze to happen on
the " best looking " frame that represents the attack. However, some
games allow the freeze to occur on multiple frames and use this as a
game element. In Street Fighter, the dragon punch is more
powerful at the best looking pose but does less damage in the after
motion. The red part of the hit points gauge in Figure 9 show the
damage caused by different impact points of the dragon punch. Better
players can time the dragon punch to hit at the peak damage.
After Attack Delay
In many games including Devil May Cry, POP:WW, and Ninja Gaiden,
after an attack motion, the character animation lingers before ending
so the player can continue the next attack even after missing the
button press timing. Although not strictly related to the impact feel,
this method improves responsiveness and the overall combat experience.
method commonly used by games in almost every genre is randomly shaking
the camera for a short period. In fighting games camera shaking may
accompany powerful or explosive attacks. On a few occasions during
development of KUF:TC, animations that looked a bit frail were
transformed into powerful attacks by a slight camera shake. So if an
impact feels flat, a quick and easy thing to try is shaking the camera
before taking time to modify the animation. Almost every attack in
Sony' s God of War is accompanied by a camera shaking (Figure 10)
more specific manipulation of the camera is shifting the camera in a
specific direction for just a few frames. This technique is used
amplify the power of the of huge sword swing in Soul Caliber 2 and Ninja Gaiden.
When the character swings the large sword horizontally, the camera is
shifted left or right for a couple of frames at the peak of the swing
(Figure 11). A vertical slam in Figure 12 causes the camera to be
shifted down. A vertical lift attack causes the camera to be shifted
up. Diagonal shifts can also be used.
heavy sword swing should be much slower than a light sword swing.
However, at the realistically slow speed, the heavy sword would be much
less useful in a game setting. So the swing is artificially made a bit
faster but augmented with a camera shift that allows it to maintain its
right before executing a two-sword beheading, the game slows down and
zooms to show the attack (Figure 13). Although the prince is not the
fastest action game character, he is one of the more acrobatic
characters. The slow motion sequences make the climactic finishing
attacks clearer to the viewer. In God of War, before some heavy attacks and mid-air grabs the game goes into slow motion to make the attacks look more powerful.
replays are more prevalent in sports games which often use them to show
highlight moments. Fighting games do show the replay of the last
moments of the battle after a round is over. In third person action
games that have limited camera angles but numerous opponents, it could
be beneficial to show the attack in different angles through instant
replays. If an attack has a wide area of effect this would allow the
player to see the attack motion close up and also view the damage
caused on enemies further away.