As mentioned on the Walkthrough page, if you select this mode, you and the other player shall have ten seconds to choose one of three difficulty levels (EASY, NORMAL, and HARD), by pushing the joystick left and right, then pressing the Firing Button to confirm your choice; once you have done this, a formation of twenty invaders (five large, ten medium and five small), along with one shield, will appear on both players' sides of the screen. Some of the invaders may be coloured yellow, red, blue, green and pink - and killing them will cause the following effects (to the other player, in case of a blue one):
| Colour | Effect |
|---|---|
| Yellow | The entire formation drops down one row (indicated by a downward-pointing arrow appearing on screen and an orchestral hit being heard). |
| Red | The entire formation drops down four rows (again, indicated by the downward-pointing arrow appearing, and an orchestral hit being heard). |
| Blue | Your opponent's entire formation drops down one row (indicated by a downward-pointing arrow appearing on screen and an orchestral hit). |
| Green | Sends the whole row to the top of the screen, while the rest of the formation drops down two rows (indicated by an upward-pointing arrow). |
| Pink | Sends the row to the top of the screen while the rest of the formation drops down four rows (again, indicated by an upward-pointing arrow). |
Also, if either player shoots a UFO while it is passing over the formation, it will swap both players' formations over, and it can make your current situation improve or worsen; in the case of the latter, you must shoot a second UFO while it is passing over the formation to swap the formations back over again, but if the invaders have almost reached the bottom of the screen for your new situation, there might not be enough time to allow another UFO to appear, but if one does appear and you cannot manage to shoot it before it disappears off the other side of the screen, you are more than likely doomed to lose.
If either player gets hit by a bullet and "killed", everything on their side of the screen will turn red for a few seconds (until they get resurrected); once one player has killed all of their invaders (or the other player's invaders have reached the bottom of their screen), they shall receive a silver (for Player 1), or gold (for Player 2) coin (but, if both players' invaders reach the bottom of their screens at the same time, the text "DRAW" will appear). Once one player has received between three and five coins, they will have won the game - and the sun will rise over the winning player's city, as the text "WIN" appears, while the losing player's city will explode and leave a crater behind as the text "LOSE" appears. The text "GAME OVER" will now appear on the screen.