CHANGES FOR THIS VERSION OF "ISLAND OF SECRETS"

"Island of Secrets" was originally a book with a type-in text adventure in
it. It had no in-game graphics, but illustrations found on the book
contained clues that were crucial to beat the game.

Unfortunately, the type-in program contained many bugs, some of which made
the game unbeatable.

This 'remixed' version can be thought of as a proof-of-concept of fixing
the BASIC program for the Commodore 64, making the game beatable as it was
intended; therefore, the solution is included so that you can test that it
works.

A few enhancements were added, which make it easier to play the game
without having the book at hand; however, some clues, which are crucial to
solving the game, are still found in the illustrations and not within the
game.


Use of string arrays
====================

The original code was written in an "as universal as possible" BASIC, such
that the number of modifications needed for each 8-bit computer in
existence was as small as possible. The code could be easily ported to
C64, VIC 20 with 16 KB expansion, TRS-80, Acorn BBC and Electron, Sinclair
Spectrum 48K.

String arrays are allocated statically on Spectrums, and for this reason
they were avoided, as the amount of RAM needed could have been excessive.
This affected two routines:

* word parsing (only the first three letters are used to recognise each
word)
* storing and printing out descriptions for places and items

The resulting coding for the latter (based on RESTORE to line number and
READ of single lines of DATA as they are needed) was optimal for the
Spectrum, but inefficient for the Commodore computers, where RESTORE
always resets to the first line of DATA, while string arrays can hold
pointers to the BASIC program itself; string arrays are thus faster than
reading several loads of DATA each time.

In this version, both routines were rewritten to be faster on a C64.

Bugfixes
========

Objects are no longer placed in wrong locations during initialisation
(making the game unbeatable).

You can no longer 'teleport' by attempting to swim from locations with no
water.

Unintended messages on some events or commands are no longer displayed:
 - upon quitting (giving up)
 - upon certain wrong inputs
 - upon using flint
 - Median repeatedly told you he could 'disable the equipment' even after
doing so

Saving and restoring games no longer results in corruption of the F()
array which disabled certain events and commands. Please note that saved
games are incompatible with the original version.

The word wrapping routine was rewritten from scratch. The old one could
break lines incorrectly on occasion.

Some problems which caused the game to become unbeatable when the player
performed some actions in an unintended order while in Omegan's sactum
have been fixed.

Input routine
=============

The INPUT command is no longer used, and was replaced with a routine that
checks for invalid characters.

Disk drive
==========

Saving and restoring now uses the disk drive at device 8. XLOAD reads the
directory and lists available games before prompting for a file name.

Enhancements
============

The player can adjust colours as preferred.

In the original version of the game, the player was not given notice of
the presence of certain objects, as he was supposed to look at
illustrations in the book and figure it out. Now the player can choose
whether those objects should really be invisible.

In the original version of the game, exits are also not visible, and
should be figured out by illustrations. Now the player can choose visible
or invisible exits.

It is now possible to examine the marble column and read the inscription
on its base. Previously, it was necessary to read it from the book.

Several pauses were replaced with 'hit any key' waits, so that the player
has time to read messages.
