Here's some new info on Acid:
"The story will apparently feature two characters who provide great assistance to Snake on his latest mission. What appears to be a new heroine is shown in some screenshots; these shots indicate that the heroine may be playable alongside Snake (although let's hope this isn't another one of those Raiden deals)."
"Screens also reveal a twist on how the storyline will be presented. For the first time, artwork similar in style to art drawn by series image designer Yoji Shinkawa will be shown on screen as characters speak their lines (the artwork is not actually from Shinkawa, though)."
/\ I don't really get that, didn't MGS do that?
"Acid is a card-based simulation that progresses as a series of missions. Missions present you with a goal when you first start off, and by clearing this goal, you clear the mission and progress through the storyline. Missions take a variety of forms, with screens in the magazine showing one mission that asks you to clear a forest via a northern path. Another type of mission asks that you use a particular card in a particular place in order to perform a particular action (that's a lot of particulars!)."
"Hmm... we're still confused, so let's continue with Kojima's comments. The gun-loving producer continues, "From the perspective of music, it's the same as 'Acid Techno' and 'Acid Jazz.' It's a new genre that emerged from the conventional 'Metal Gear' genre. We call it 'Acid Metal.' Of course, the creators of the game are different from 'Solid.' 'Acid' offers a new fashion for young people from young developers. That's 'Metal,' and the new 'Acid Metal.'"
...Ok Kojima...
http://psp.ign.com/articles/541/541291p1.html
It sounds very different from any card game up till this point.