In Catacomb 3D
In Catacomb 3D, the player runs into two different kinds of Gate, though they look identical to one another. The first kind is a teleportation gate that will move the player around between different locations on the same floor; the other is the kind that will function as the end-of-level marker and will move the player to the next area. Because the two are indistinguishable from one another visually, the only way to know what lies beyond a gate is to head through it. Gates in Catacomb 3D are bright blue swirling vortexes of energy, and are mostly created by Nemesis, using Grelminar's stolen power.
Because Catacomb 3D has a level of non-linear design, there are multiple routes through the game, but the player must beware, for two reasons:
The first is that while a hidden gate can get the player through the early game much faster, they will miss out on valuable treasure caches that can help the player later on, such as Bolts, Nukes, and Cure Potions. A few Gates lead to unique secrets or shortcuts, but will bypass these critical supplies.
The second is that some of the Gates are, in fact, traps. Of particular note is a series of Gates in the Halls of Blood; only one of these gates - the one with no items near it - leads to Nemesis's Lair. All the other gates in Halls of Blood will instead dump the player back at Access Floor! Because of this, it may be a good idea to save before heading through a gate.
In the Catacomb Adventure Series
The Gate returns in the Catacomb Adventure Series, now mostly used to move players between different areas on the same floor, since locked exit doors are now normally used to demarcate the end-of-level transitions in these games.
There are a few exceptions, such as the Well of Souls in Catacomb Abyss, or Time Gates in Catacomb Apocalypse, but these are relatively rare and are, for the most part, clearly marked. Teleportation Gates have a very distinctive stone doorway surrounding them now, with either a blue glow (Abyss) or Red glow (Armageddon, Apocalypse).
In Sylvan Idyll
In Dark Designs
The Dark Designs trilogy of role-playing games by John Carmack has the player trying to recover the long dead Grelminar's staff to close a dimensional gate at Mount Delkeina that is unleashing an army of demonic invaders.
|Petton Everhail - Grelminar - Nemesis
|Orcs - Trolls - Bats - Mages - Demons - Fireballs
|Magick Missile - Cure Potions - Treasure Chests - Keys - Bolts - Nukes - Scrolls - Gates
|Petton Everhail - Nemesis
|Zombies - Bats - Wraith - Skeleton Warriors - Mages - Blue Demons - Water Trolls
Orcs - Green Trolls - Evil Eyes - Red Demons
|Magick Missile - Cure Potions - Treasure Chests - Keys - Zappers - Xterminators - Scrolls
Jewels - Crystal Sphere - Gates - Crystal Hour Glasses
|Petton Everhail - Nemesis
|Zombies - Giant Ants - Treants - Bats - Killer Rabbits - Mages - Skeleton Warriors
Vipers - Two-Headed Demons - Wretched Poxes - Evil Eyes - Succubi - Sea Serpents
|Magick Missiles - Cure Potions - Treasure Chests - Keys - Zappers - Xterminators
Jewels - Crystal Sphere - Gates - Crystal Hour Glasses - Barriers