Secrets around Trinsic
Trinsic Cheat Room
This is accessible at the very beginning of the game, before you've even done the copy-protection test (this can therefore be used to bypass it). Simply take the crates from Christopher's smithy and stack them to make a staircase up to the roof. Walk onto the roof and behind the chimney to enter the cheat room.
You'll end up in the room inset to the bottom-right of the picture. Hit the switch to open the metal door. Take what you want from the chests, or step onto the teleporter to end up in another corridor. Go along that corridor to enter the larger room.
The numbers refer to sextant coordinates (or ones as close as can be determined, some areas are inside where the sextant naturally doesn't work).
All items on teleporters act identical to their legal in-game equivalents; the gold can be spent, the Cadellite Helm worn, etc.
From Trinsic head SW until you reach 128S, 4W. Look for a chest almost entirely hidden by some trees. Drag it out into a clear area. The key is under a dark stone half-a-screen south-east of the tree.
It contains a full set of magic armour, 600 gold coins, a crossbow and some magic bolts, not to mention a Sword of Defense, a Fire Sword, some swamp boots (equip these) and three rings. The Fire Sword is especially valuable; with it equipped you can explore dark caves without ever worrying about torches and their limited lifespan.