Akkanvader/Gameplay

Controls

 * Joystick: Use the 2-way joystick, to direct your chosen ship along the bottom of the screen; none of them can wrap round from one side to the other.
 * Firing Button: Use this button to make your chosen ship fire bullets up at the invaders; holding it down charges the shot (much like the R9 in Irem's R-Type), and upon releasing the button the ship fires a more powerful shot up at the invaders. Every ship has their own unique type of shot.
 * 1 or 2 Player Buttons: Push these buttons to begin the game as player 1 or player 2; the choice determines which of the characters you may select.

First-player pilots
The Silver Hawk originally appeared in Darius back in 1987, while Sayo-Chan originally appeared in KiKi KaiKai a year earlier in 1986 - and both have also appeared in the eighth and seventh stages respectively of Space Invaders DX's "Parody Mode" in 1994; for the US version, Kusai-Wa 1 was renamed to "Toilet I", Poribaketsu 1 to "Bucet I", Wanko to "Harry", Clyde is misspelled as "Cride", and Goriyaku Ichi renamed to "Amulet I". The descriptions of the ships that appear during the attract mode are also changed to feature badly-translated "Engrish" phrases.

Second-player pilots
In the US version, Kusai-Wa 2 was renamed to "Toilet II", Danboru-Bako 2 to "Corrugated Carton II", Nyanko to "Nancy", Bonnie misspelled as "Bonny", and Kaiun Ni was renamed to "Amulet II"; this also meant that the character of Nyanko was changed from a male (the only one on 2P side), to a female.

Regular Invaders
The alien invaders still behave the same (again); they remain in formation (as they advance towards the bottom of the screen). The entire formation will either circle around as they move downwards, move to the right or the left until the far column reaches the side of the screen then drop down and move back towards that other side of the screen, or move downwards - and, the lowest invader of every column shall fire bullets down to the ground (and you will receive 10 extra points for every one you block, or for those that cannot be blocked, attempt to). If any one invader manages to reach the bottom of the screen, both players will die immediately as the Katakana text Inbēdo (インベード) for the Japanese version or the English text "INVADE" for the US version, appears on the screen (but, like in Majestic Twelve, your game will not end; the invaders will just return back to their original starting positions).

Type 33 Invaders also serve as UFOs in World 4, and Type 34 Invaders also serve as shields there (but shall occasionally fire three bullets into the air).

Bonus Invaders
These types of invaders only appear on the "Bonus Stages" (4, 10, 18, 25 and 31); they will fly into view from the left side, right side or top of the screen and you can kill them, for bonus points. At the end of the stage, the amount of bonus points you received for the killed Bonus Invaders will get tabulated.

UFOs
As in all six previous games, UFOs shall appear randomly over the formation; they appear on one side of the screen and cross over to the opposite side. During this time you can attempt to shoot them for bonus points - however, the point value that is awarded for one can now only range from 500 to 3000.

The Bonus UFOs are common to all five worlds of this game, and when they are destroyed, they shall leave one of four different powerups behind which shall fall down to the bottom of the screen and bounce three times before falling off it (for a two-player game, the third of them will work for both players):
 * AV Powerup Bowling Ball.gif Bowling Ball: When either player collects this powerup, they will receive a large bowling ball; when they press their Firing Button, they will roll it, and it shall bowl over any invader it hits. This is particularly useful for stages where the invaders adopt a vertically-moving formation.


 * AV Powerup Missile.gif Missile: When either player collects this powerup, they will gain that ability to fire more rapidly for twenty normal (non-charged) presses of the Firing Button; this is particularly useful for certain stages, where the invaders move at a faster speed than those on some other stages.


 * AV Powerup Clock.gif Clock: When either player collects this powerup, all invaders currently on screen shall stop moving as an "eyeless" alarm clock appears at the top of the screen; once it's reached the time of 11:05, it shall ring and disappear, and all the remaining invaders will start moving again.


 * AV Powerup Bomb.gif Bomb: When either player collects this powerup they shall receive a large bomb; when they press their Firing Button, they will throw it into the air, and it shall kill any invader in its blast radius when it explodes; this is particularly useful for stages where there are lots of invaders.

Type 1 UFOs also play the part of regular invaders on Stage 27, where they shall adopt a horizontally-moving formation, and for the first time fire bullets.

Boss Invaders
World 1 (Stage 5): Once your two chosen ships have stopped moving on forward, the first Boss Invader will drop down into view from the top of the screen and speak the threescript text Kondo ha, 'bosu' no oresama ga aitedā!! (今度は、「ボス」のオレ様が相手だー!!) in the Japanese version, or "THIS TIME, I, THE BOSS FIGHT AGAINST YOU!" in the US version; he will now start flying around up above you while spewing a volcanic hail of bullets and bombs down at you (the latter of which can get blocked, for extra points). He'll then throw two bowling balls down at you, and spew out twenty-four small versions of himself - which will adopt a vertical formation as they descend towards the bottom of the screen, so you shall have to kill them as well. Once you have fired out enough shots at him to defeat him, he will explode, and speak the Hiragana text Chikushō, oboe terō!! (ちくしょー、おぼえてろー!!) in the Japanese version; you'll then receive 10000 bonus points, as your chosen pilots speak the Kanji/Hiragana text of ''Rakushō! Chō rakushō! Pīsu!'' (楽勝! ちょー楽勝!! ぴいすっ!) (in the Japanese version), or "WALKAWAY!! A VERY EASY VICTORY!" (in the US version). You'll now proceed to World 2, which appears to be based on food.

Note: If either, or both, of the players selects Benben and/or Penpen in both versions of the game, they will speak random toilet-related symbols instead of the standard phrases, and if either or both of the players selects Wanko and/or Nyanko in the Japanese version, they'll only speak the Hiragana texts of Wan (わん) and Nyan (にゃん), as they are Japanese onomatopoeia for barking and mewing; in the US version, where they were renamed to "Harry" and "Nancy" (the latter also becoming female), they'll only speak the texts "BOW" and "MEOW" instead, as they're English onomatopoeia for the same.