minecraft can be played on:
no
Yes you can, but you need to download minecraft for macs
Clear all the Minecraft folders on your computer and don't use the same Minecraft name :D
right click to throw an enderpeal
Minecraft doesn't mess up your computer. Minecraft is a malware free program.
The best way is to use fraps.Alot of minecraft commentators use it.
no you can not
Yes, you can download and install mods on the PC version of Minecraft, there are several gun mods you can apply.
If you use MultiMC you can have multiple copies of Minecraft installed on one computer, with different versions and mods.
you need the pc version on the computer
Minecraft is made to work with ANY computer that uses java.
It depends. If you are using a public computer, it will be a monthly fee. If you use anything other than a public computer, it is free. A better explanation can be found on Minecraft Wiki.