MUTANT'S REVENGE for Sinclair ZX-81
by Martin Hargreaves
from Your Computer, March 1985

Mutant's Revenge is for the 16K ZX-81. The principle of the game
centres around the arcade classic Defender, except you are one of the
mutants.

The object is to guide your mutant onto a humanoid, capture it and
take it skywards. Sounds easy? As you will find out, it is very hard
and will take some mastering.

The program itself has everything the average computer game freak
wants. Fast, original, good graphics, Hall of Fame, 100 skill level,
etc.

Line 1 should contain at least 94 full stops. On line 1530 it mentions
"12*GRAPHIC G"; this means that you must type in the graphic "G"
character 12 times.

When it has all been keyed in you must save before running. To save
type GOTO 1890; this saves the program with the name "MUT" and runs
automatically on loading. There is a variable in this program called
AT; this should not be confused with the keyword AT.

When you run this program your ZX-81 will move into FAST mode to load
some machine code. You do not need to type in hex or decimal codes
blindly, as the program has it all in memory at line 20 and a built-in
interpreter. As soon as the machine code is loaded it is executed
twice using RAND USR 16514.

You will then be asked at what speed you wish to play - 0 to 9. Note
the absence of an input sign to avoid data entry errors. Then you are
asked for the fuel consumption rate, again in a range of 0 to 9 and no
input sign.

When both the skill levels have been entered a neat little routine
will display what keys are needed to control your mutant. This gives
you time to fumble about and get your fingers over the right keys,
which are:
	Q = up
	A = down
	O = left - thrust
	P = right - thrust
	1 = hyperspace

Your first job is to capture a humanoid "O"; these are randomly
scattered across the landscape. Your mutant is situated at the far
left-hand side of the screen steadily moving right. The O and P keys
serve as thrust and reverse keys. This means that if you press O your
mutant will keep moving left unless told otherwise. These features
make the mutant more manoeuvrable as it can move in diagonals. If it
hits the far left/right hands of the screen don't worry as it will re-
appear on the other side. When you hit a humanoid you will be awarded
10 points - this will be shown on the "score" gauge and the humanoid
gauge will decrease by one.

Once you have captured a humanoid phase two begins; this involves
taking the humanoid skywards. Your mutant moves up automatically so it
is just a job of avoid pyrenoids and the gate. The gate is a hole
situated at the top of the screen which moves from side to side.
Pyrenoids are asterisks which float in the sky - contact with one will
prove fatal. If you manage to carry your humanoid through the gate you
are awarded a mystery amount of points and you will return to the left
of the screen to try and capture another.

If all the humanoids have been captured you are said to have completed
an attack wave and a bonus of 30 points will be added to your score.
When all the humanoids have been captured you will go on to the attack
wave sequence. Sometimes, however, your mutant will return to the left
of the screen even though there are no corresponding humanoids. In
this case just move through the gate and move to the top of the screen.

If you score 500, 600 or 800 then you will be awarded an extra man and
the game speed will hot up. The screen will clear and another random
landscape will be drawn and play will continue.

This program is fitted with a special key which, when pressed, shoots
you out of trouble and throws your mutant into a random position on
the screen.

