Bukkit

Elements

Portals

Most essential thing in this plugin. Grab wooden stick into your hand, and click with left mouse button to shoot blue portal and click right mouse button to shoot right portal. You can only create portals on iron (changeable in config).

Pretty much anything can travel through portals (players, boats, minecarts, mobs, dropped items, water, lava, fire, ignited tnt, falling sand, falling gravel, arrows, ... Missing anything? Open a ticket).

Portals can also carry momentum. For example if you fall with high speed into one portal, you will fly out of the other portal with high speed.

Demonstration:
http://www.youtube.com/watch?v=BHxduNH5kVY (at around 00:20 and 01:00)

Portal Equivalent:
http://half-life.wikia.com/wiki/Aperture_Science_Handheld_Portal_Device

Aperture Science Material Emancipation Grill

This element will make sure that your test subjects are not smuggling items or portaling between test chambers. When someone walks through, it would delete all his portals, clear his inventory (with exception of stick) and deleting all dropped items, making all pressure plates reset and prepare test chamber for next participant.

You can build it by creating frame of mossy cobblestone, including corners. Frame can be any size or shape. Then light any mossy cobblestone in frame on fire using flint and steel. You can remove grill by simply breaking one of the blocks in frame.

The frame is redstone sensitive, that means you can disable the grill with redstone.

Demonstration:
http://www.youtube.com/watch?v=BHxduNH5kVY (at around 0:30),
http://www.youtube.com/watch?v=yWW-ssv9saE (at around 00:02 and 00:58)

Portal Equivalent:
http://half-life.wikia.com/wiki/Aperture_Science_Material_Emancipation_Grill

Aperture Science Aerial Faith Plate

These hi-tech devices will launch you into the sky.

There are two versions: floor and wall. Floor one can be made by placing two diamond blocks next to each other and then placing stone pressure plate at one of them. For wall version, simply place diamond block in the wall and player will bounce away from it.

Demonstration:
http://www.youtube.com/watch?v=bAMz9BOJY2o (at around 00:37)

Portal 2 Equivalent:
http://half-life.wikia.com/wiki/Aperture_Science_Aerial_Faith_Plate

Repulsion Gel Block

Repulsion Gel or simply "blue gel" will bounce you off surface. It functions similar to Aperture Science Faith Plate, except that its bounce power is not predetermined, but based on player speed. So if player will fall to it at high speed, it will also bounce at high speed.

All blue wool blocks (except portal blocks) will function as Repulsion Gel Block.

Demonstration:
http://www.youtube.com/watch?v=bAMz9BOJY2o (around 00:03 and 02:20)

Portal 2 Equivalent:
http://half-life.wikia.com/wiki/Repulsion_Gel

Propulsion Gel Block

Propulsion Gel or simply "red gel" will speed player up when running on it. This can be useful to jump across gaps.

Any orange wool blocks (except portal blocks) will function as Propulsion Gel Block.

Demonstration:
http://www.youtube.com/watch?v=bAMz9BOJY2o (around 01:01 and 02:20)

Portal 2 Equivalent:
http://half-life.wikia.com/wiki/Propulsion_Gel

Infinite Dispensers

This feature will allow you to keep dropping items from dispensers without the need to refill them. This can be used to deliver items to your test subjects.

Just place item in dispenser's center slot and it will be infinite.

Also, make sure that you properly restrict PortalStick's function (either through disabled worlds or locations), so your players cannot duplicate items in dispensers outside of portal zone.

Portal 2 Equivalent:
http://half-life.wikia.com/wiki/Aperture_Science_Vital_Apparatus_Vent

Gel Tubes

Gel tubes are Infinite Dispensers filled with a Gel Block. They shot out Gel as long as they have power and remove all shooted Gel when power gets off.

Hard glass bridge

Hard glass bridges are still pretty bugged, don't cry when it's not working. You can help me much by opening support tickets (after you checked if there isn't already made a ticket for your problem) about the bug so I can fix it. Hard glass bridges are bridges that go through portals. So you can also make the environment more interactive.

You can make them by placing two iron blocks, with a empty block between, and a redstone torch on them, Like as in the picture. Then light one of the iron blocks.

The iron blocks are redstone sensitive, that means you can disable the bridge with redstone.

Portal 2 Equivalent:
http://half-life.wikia.com/wiki/Hard_Light_Bridge