DemonAttack¶

This environment is part of the Atari environments. Please read that page first for general information.


Action Space	Discrete(6)
Observation Space	Box(0, 255, (210, 160, 3), uint8)
Import	`gymnasium.make("ALE/DemonAttack-v5")`

For more DemonAttack variants with different observation and action spaces, see the variants section.

Description¶

You are facing waves of demons in the ice planet of Krybor. Points are accumulated by destroying demons. You begin with 3 reserve bunkers, and can increase its number (up to 6) by avoiding enemy attacks. Each attack wave you survive without any hits, grants you a new bunker. Every time an enemy hits you, a bunker is destroyed. When the last bunker falls, the next enemy hit will destroy you and the game ends.

For a more detailed documentation, see the AtariAge page

Actions¶

DemonAttack has the action space of Discrete(6) with the table below listing the meaning of each action’s meanings. To enable all 18 possible actions that can be performed on an Atari 2600, specify full_action_space=True during initialization or by passing full_action_space=True to gymnasium.make.

Value	Meaning	Value	Meaning	Value	Meaning
`0`	`NOOP`	`1`	`FIRE`	`2`	`RIGHT`
`3`	`LEFT`	`4`	`RIGHTFIRE`	`5`	`LEFTFIRE`

Observations¶

Atari environments have three possible observation types: "rgb", "grayscale" and "ram".

obs_type="rgb" -> observation_space=Box(0, 255, (210, 160, 3), np.uint8)
obs_type="ram" -> observation_space=Box(0, 255, (128,), np.uint8)
obs_type="grayscale" -> Box(0, 255, (210, 160), np.uint8), a grayscale version of the “rgb” type

See variants section for the type of observation used by each environment id by default.

Rewards¶

Each enemy you slay gives you points. The amount of points depends on the type of demon and which wave you are in. A detailed table of scores is provided on the AtariAge page.

Variants¶

DemonAttack has the following variants of the environment id which have the following differences in observation, the number of frame-skips and the repeat action probability.

Env-id	obs_type=	frameskip=	repeat_action_probability=
DemonAttack-v0	`"rgb"`	`(2, 5)`	`0.25`
DemonAttack-ram-v0	`"ram"`	`(2, 5)`	`0.25`
DemonAttack-ramDeterministic-v0	`"ram"`	`4`	`0.25`
DemonAttack-ramNoFrameskip-v0	`"ram"`	`1`	`0.25`
DemonAttackDeterministic-v0	`"rgb"`	`4`	`0.25`
DemonAttackNoFrameskip-v0	`"rgb"`	`1`	`0.25`
DemonAttack-v4	`"rgb"`	`(2, 5)`	`0.0`
DemonAttack-ram-v4	`"ram"`	`(2, 5)`	`0.0`
DemonAttack-ramDeterministic-v4	`"ram"`	`4`	`0.0`
DemonAttack-ramNoFrameskip-v4	`"ram"`	`1`	`0.0`
DemonAttackDeterministic-v4	`"rgb"`	`4`	`0.0`
DemonAttackNoFrameskip-v4	`"rgb"`	`1`	`0.0`
ALE/DemonAttack-v5	`"rgb"`	`4`	`0.25`
ALE/DemonAttack-ram-v5	`"ram"`	`4`	`0.25`

Difficulty and modes¶

It is possible to specify various flavors of the environment via the keyword arguments difficulty and mode. A flavor is a combination of a game mode and a difficulty setting. The table below lists the possible difficulty and mode values along with the default values.

Available Modes	Default Mode	Available Difficulties	Default Difficulty
`[1, 3, 5, 7]`	`1`	`[0, 1]`	`0`

Version History¶

A thorough discussion of the intricate differences between the versions and configurations can be found in the general article on Atari environments.

v5: Stickiness was added back and stochastic frameskipping was removed. The environments are now in the “ALE” namespace.
v4: Stickiness of actions was removed
v0: Initial versions release