1 I just finished watching it and frankly, about the only thing it had going for me is that it didn't take place in a school. Okay, and I kinda liked Plutia's HD form and how she got away from the whole Saccharine goddess thing.  I didn't get why the witch's name and the subtitle for her didn't match at all.

I totally didn't get Neptune's attachment to Peashy. (I know, I'm massacring the names right now).  Hmmm, PC?

And I wasn't sure where Compa and IF fit into the scheme of things.  Nobody else had assistants like that.

And frankly, I didn't quite see the appeal of that online world to the regular users.

2

The Wikipedia page would help you, I think. There's a whole lot of industry in-joking going on.

Compa represents the company "Compile Heart", which developed the game.

IF is "Idea Factory", which owns Compile Heart.

As to the names, a lot of the Japanese originals are strange in English. So "Pururuto" became Plutia when the games were translated for the North American market. And when the anime was subtitled, the subbers stuck with the new names.

Re Arfoire:

Her English localization name is based off the R4, a Nintendo DS game card which allows the owner to play pirated games. In the Japanese version of the game her name is Magiquone (マジェコンヌ, Majekon'nu^?), which refers to magicom (マジコン^?, "magic computer"), a Japanese umbrella term for devices that enable piracy on game consoles.

3 Translated satire, puns & idioms normally lose a lot.  I've gotten a solid number of jokes off non-native English speakers with "Keystone Cops" jokes.