Level and LevelB are two programs which will allow you to
play Thexder at any level you want. However, there are some
drawbacks. Level will allow you to play any level you want,
but you must first play through levels 1-3. After completing
level 3, you will go on to the level you selected. This allows
you to see all the creatures as they were intended. LevelB allows
you to play any level you want without having to play through the
first three levels. You begin at the level you selected. But if
you select a level higher than 3, you will not be able to see the
creatures as they were intended. They will appear as squares of
static. Their movement will be the same. An interesting aspect
of levelB is that if at the beginning of play, you do not proceed
forward as you regularly would, but go backward, your laser cannon
will fire from some distance ahead of you. Additionally, the
creatures will be attracted to where the laser is originating from
instead of where you appear to be.

The command line for both programs is as follows:
LEVEL [level to play]
or LEVELB [level to play]

After playing the selected level in the LEVEL program, you
will proceed to play level 5, level 6, and so on.
After playing the selected level in the LEVELB program, you
will proceed to play level 2, level 3, and so on.

When you are through playing, be sure to Quit by pressing
Q once in the game. Turning off the power without allowing
the LEVEL or LEVELB program to reset the files will cause
a great deal of confusion the next time you try to play.
Be sure to have a backup copy of Thexder in case you forget.
Enjoy!