"Kill the attacking aliens" (KTAA) is a fast shoot-em-up game for Odyssey², Videopac G7000 and Videopac+ G7400 video game consoles.
Xype is a group of programmers for retro video game consoles who created a recognizable name for exceptional video games. Shortly after the KTAA release I have been asked to join Xype and KTAA is now the 10th game released under the Xype name. To learn more about the other games Xype has released visit the Xype home page.
Congratulations! You have been selected as pilot to defend the planet earth and its moon colony against alien invaders. Your ship is equipped with a powerful quantum cannon and a strong defense shield. Your mission is to shoot all the aliens while trying to prevent the objects on earth from being bombed.
Set up your Videopac or Odyssey² as usual and turn it on. The normal "SELECT GAME" screen should appear. Press the key 1 to continue. If you own a Videopac+ G7400 and want to play the game without the additional background graphics then press the key 0 instead.
The title screen shows the name of the game and a scroll text. It alternates with the score display. The score display shows the score of the last game played and the highest score achieved so far. On the title screen press the action button of the right joystick to begin a new game. You see a screen which shows the level, score and current shield strength. Press fire again and the game starts.
Move your ship with the joystick and press the action button to shoot at the aliens and their bombs. Avoid collisions with the aliens and the bombs, they reduce your shield strength. If you touch a bomb with your ship the bomb will explode, but the aliens have stronger shields, they survive direct ship contact.
If you hit an alien or a bomb a power-up may appear due to the quantum effects generated by your weapon. You can activate those power-ups by hitting them again with your cannon or by direct ship contact.
After you shot down all aliens in a level you get bonus points for the objects still intact. If you managed to save every object you get an additional 250 points bonus. After the bonus is counted the game advances to the next level.
After you have shot down all aliens in level 7, the moon level, the game starts again with level 1, but now your cannon shoots slower shots. The next wave of aliens will shoot more often every time you win level 7.
If your shield strength drops to zero your ship explodes and the game is over. The game is also over when all objects at the ground are destroyed by the alien bombs.
This power-up just adds 10 points to your score. It is the most common type of power-up.
The fast shot power-up increases your shot speed for a short time. The shield display turns red while this power-up is active. If you collect another one while it is active the time restarts.
The alien slow down power-up slows down the aliens and their bombs for a short time. If you collect another one while it is active the time restarts.
The shield power-up refreshes one unit of shield strength. If your shield has already full power nothing happens. This power-up is the most seldom one.
You can run this version on a real machine or use the o2em emulator, see this tutorial for more information on using o2em. KTAA does use some features not used by any other game, so there are some minor problems with the gfx on o2em version 1.01, some of the objects you have to defend don't stop at the ground. This is not a bug in KTAA, so please don't report it.
The easiest way to get KTAA on carts is to buy them at Packrat Video Games.
If you have access to an EPROM burner and some knowledge in soldering you can create your own cart. See inside the KTAA distribution archive for more information or look at my page with cart pcbs.
The following screen shots are taken with o2em 1.01.
| Level 1 | |
|---|---|
![[Image]](../images/ktaalvl1.png) |
This is the first level, a house inside a forest. |
| Level 7 | |
![[Image]](../images/ktaalvl7.png) |
This is the last level, the moon level. |
I started KTAA somewhere in 1998 while experimenting with the graphic capabilities of the Videopac G7000. I created a display very similar to what is now level 1 and had the idea to create a game. I rewrote the graphics engine so often that there is now no trace of the original code left. I never thought it would take so long to finish it and have sometimes not touched it for months because I was too frustrated to work on it.
Several people helped me with ideas and testing during the development of KTAA. Without their work KTAA would be much worse or even never finished.
René van den Enden did lots of testing and had many suggestions to improve KTAA.
Rafael Cardoso suggested the train level.
The O2EM emulator was a great help during development, its internal debugger made debugging much easier. So I want to thank Daniel Boris for creating O2EM and André Rodrigues de la Rocha for maintaining and improving it.
I also want to thank all those people who sent me encouraging mails, they showed me that it was worth finishing KTAA.