yes
You need to buy Portal in order to play the mod Portal: Prelude.
In order to play the mod Portal: Prelude, you do need to have Portal.
You need a perpetual calendar. Google perpetual calendar.
To answer this question we need to know the initiative you have in your question.
In order to to the nether you need a portal.
Yes, it use Portal's character models and game engine. You might also need Source Base.
The universe is perpetual as we know of so far.
No, you do not need a mod to create an Aether portal or an End portal in Minecraft. The End portal can be built using End Portal Frames and Eyes of Ender in a specific arrangement, while the Aether portal is not part of the base game and typically requires a mod or custom server. The Aether is a separate dimension introduced by mods, while the End is an official part of the game.
You need steam to install Portal 2 Why not? It's free
No version, you need a mod called The Aether to get the portal. Make sure the Mod is up to date.
You will need 14obsidian if you are going to place obsidian on the corners of the portal, but if you fill in the corner of the portal with other blocks, then you will only need 10.
Its a machine that has to be started but doesn't need to be restarted.