Treasure Crypt was a game which featured on the Jagex and Games Domain sites during and around 2000. It is possible that it is an early version of Dungeon Assault however since it featured on the site at the same time as Dungeon Explorer which is most likely to be the original Dungeon Explorer.
When it was online it's description read:
Search for treasure, gather people to your party, and fight monsters in the crypt exploring sensation. Part of the Castle-GamesDomain multiplayer games suite.
The instructions for it read:
Objective of Treasure-Crypt
You must enter the Treasure Crypt and try to collect more treasure than your opponents, but watch out for monsters and earthquakes. The winner is whoever escapes with most treasure, or the last person left alive!
How to play
On your turn choose which way you want to move by clicking on the arrows at the bottom right. Your player will walk to the new location. If it is a corridor then you enter the new location and your turn ends. If you discover a room then it's contents will be randomly determined and displayed! You must now choose what action you will take from the choices shown on the left.
People and enemies
If you meet a person you can ask them to join your party, they will randomly either be friendly, neutral or hostile. If they are friendly they join your party, but if they are hostile you must fight them. If you attack an enemy without talking you get a +1 bonus for a suprise attack, but if they attack you get a -1 penalty! You can normally also retreat, for which there is no penalty except a wasted turn.
Treasure and Objects
If you find objects you can choose to pick them up, unless they are guarded by someone else in the room, (in which case you must talk to or attack them first). Each charactor can only hold a limited amount of objects, so you may need to drop less valuable objects. Do this by clicking on the object in the display at the top of the screen, you can then either move it to another player or drop it.
Each person/creature in the game has a different strength and ranged-combat rating. In combat each parties strength is determined by the joint strength of the 2 strongest members, plus the total ranged strength. A random number from 1 to 6 is then added to this, and whichever side gets the higest number wins the combat. If you win then all the enemy creatures die. If you lose one of your front 2 charactors is randomly killed, and any objects held by that charactor are dropped.
End of the game
The game ends either when only 1 player is left alive, or after a certain number of locations are revealed. At the end of the game you must make sure you have a route back to the exit, (i.e you aren't trapped by an earthquake) or else you lose! All of the surviving players scores are then totalled and whoever has most wins the game.