Metal Gear Acid is turn based. Here's some thoughts I posted elsewhere:
Fundamentally, it's a turn based strategy game using cards to decide
actions, with a heavy emphasis on stealth. It's not as odd or out
there as that sounds - ignoring the cards, it's like a version of XCom
or FFT with only one player controlled character. The levels are like
MGS levels but with a grid overlay. Characters take turns to move &
act.
The big difference is in how you decide whether to move or act, and
what actions to take. Before each mission, you choose a deck of 30
cards from your repetoire, such as various pistols/grenades etc,
health packs, equipment like armour or dodge, special attacks like
Ninja. As you play the mission, you're dealt a random hand of these
cards which you can either use or move with - selecting move throws
the card away effectively. Without a weapon card in your hand, your
only attack option is a simple punch. When you go through all 30
cards, the deck is shuffled & dealt again.
There are overarching rules/costs to using cards obviously, with each
card having a "cost" that modifies turn speed etc. When you've used 4
cards or too much cost, your turn ends & passes onto the next enemy.
So a mission consists of you using cards to move around the MGS-like
map, waiting for your enemies to turn their backs to you for you to
sneak past or kill them. Sometimes you don't have the cards you need -
it's easy to end up with a hand empty of guns for example.
Your performance in each mission is ranked of course, with bonuses
awarded for fulfilling three targets, i.e. "no kills", "fast" &
another I don't know

Missions can be repeated. Inside each mission
are bonus cards to pick up that get added to your selection... Points
can be spent on new cards in between missions too.
The story & scenario... Well, the story is classic Metal Gear Solid
hodgepodge hokum so far.
Graphics & sound are
very similiar to the PSX Metal Gear Solid
game from what I can remember of it. Controls/interface is nice &
straightforward, and there's a mid mission save option too, which is
very handy for a game of this nature.
So far, I'm really enjoying it. The intro sequence is long & utterly
ignorable, which for me made it hard to get into - there's a good five
minutes before you actually get to do anything - once I got past that,
it really grabbed me.