You can always just get the Japanese version of a game you enjoyed in English, which makes it much easier to figure out which commands and menu entries are which. This is how we did it- puzzling through Katakana came later.
Kain's up, so the commands are Attack, Jump, Item.
(This means you also have the opportunity to learn how to call someone a Spoony Bard in Japanese. That really should be in every phrasebook.)
Now here's just about my most flailed series of all time- the one I plucked the menu screen from for yesterday's FIY. Super Robot Wars (Or Super Robot Taisen if you really prefer) is a series of simulation games much, much lighter on the strategy and number-crunching than Gihren's Greed. And once again, it will never make it to the US- at least not in its purest form. The villain here is the licensing fees: the main SRW series is a mashup of giant-robot anime from Mazinger-Z to Gundam to Evangelion and well beyond, featuring adorable little Super Deformed versions of things like Evas, which you wouldn't think could be adorable.
Aw, so cute! I wonder who it's about to eat?
Naturally you're going to get more out of it if you've seen some or all of the series involved: while the overarching plot apparently tries to combine all the series into one seamless storyline, individual stages are usually based on specific battles from the anime series that the game's robots hail from. There are bonuses of various kinds for following the plot of the series- finishing enemies in the right order, or with the right attack, and so on.
There is money, and some stuff to buy, but for the most part you're going to be worrying about damage and range numbers instead of resources and alignment. Every stage takes place on a grid, and movement and attack are pretty easily decipherable even in Japanese. It's actually not too bad to play through, with a few minor hiccups. You'll get shown a space on the map, and you may have to escort specific units to them, or keep the enemy from entering, or get your entire army there yourself. Watch for dialogue with numbers in it as turns begin; you may have a time limit to beat the stage. Or escape the stage. Or something. In most of the games you can save at any point, and I recommend it.
If you want to ease into the system before flailing your way through with your favorite robots, there are a pair of Original Generations games available in English for the Game Boy Advance. They don't feature any licensed robots, paring the series down to just the characters, plot points and machines created by Banpresto to glue all the licenses together. There's also a spinoff called Endless Frontier for the DS- I haven't played it, but judging from the screens I've seen I can determine that the character designer is a straight male and had way too much fun with the assignment. When you import, the best experience will come from the PS2 or PSP; hearing the original voice actors scream attack names in Japanese really adds something fun to the experience.
Japanese games are actually full of helpful English words that can give you a vagueish clue as to what you're doing! ...unfortunately, these are all written in katakana, which have no relation to the Roman alphabet or the sounds it produces. There are also some sacrifices and shortcuts based on the fact that English sounds that we take for granted just do not exist in Japanese. B sounds are usually substituted for Vs, S for TH- which is why Cloud mentions a "Sefiros" in the original PS1 version of Final Fantasy Tactics, and why the Aeris/Aerith controversy rages to this day.
So, what should you be looking for when it's time to save your game? That would be Se-Bu.
This is another one you will see some variation of in practically everything you flail through. Next time, more katakana!
Giren's Greed is a series of deep military sims that will never, ever be published in English. There's a variety of reasons for this: Strike One is that deep military sims tend to be a niche market to begin with. Strike Two is that the amount of translation and voiceover necessary makes it a pretty expensive project for that small market. Strike Three is that it's based on the Mobile Suit Gundam anime series- in Japan, this is the equivalent of being based on something as big and as beloved as Star Trek. In the US, this means your game will sell to a tiny contingent of Anime and Robot nerds like me. Worse yet(Strike... Four?), the original Gundam continuity never caught on here to the degree that its spinoffs and alternate universes did, so you're talking niche-within-a-niche-within-a-niche. It's a shame, because even though I get impatient with them I do like to play games that require some thought.
While some of the games in the series have a broader scope, they all cover at least the One Year War, the time period of the original Gundam anime and most of its spinoffs. Bear in mind, this is a time period that has been added to, revised and retconned to death by both fans and Gundam's parent company Sunrise for thirty years. So to get the most out of the series you need nigh-encyclopedic knowledge of the Universal Century's history, which you could call "rich" if you were feeling generous, "convoluted" if you were feeling slightly less generous, and "self-contradictory and confusing" if you were being realistic.
The game I played, Axis no Kyoui for PSP, starts a few months into the War, where you play either the resource-rich but technologically stunted Earth Federation or the advanced but limited-in-funding Principality of Zeon. In anime terms the Earth Federation are the good guys, at least by virtue of the main characters of the series being in their employ. Gundam is at least mature enough to not paint either side as completely saintly or bloodthirsty. I played the Federation because (three decade old spoiler alert!) they're the ones who actually win the war. To do this, though, you have to hold off Zeon until you develop the Mobile Suits you need to counter them, and hopefully push them back and expand your production capabilities. In both the anime and the game the Federation's greatest strength is its size and its ability to spam Zeon with Suits just slightly better than the bulk of Zeon's forces. Zeon wastes a lot of time on wild-eyed prototypes and expensive one-off behemoths, and while they can hurt you, nobody's that effective when they're waist-deep in GMs.
In terms of a blind Flailthrough, this game is utterly impossible. Everything is Kanji, and you have to manage your forces, your budget, and even your alignment, as certain actions are impossible if you're Chaotic- the Federation is nominally a democracy and the people won't pony up extra taxes and resources if you're a jerk. There's a dedicated wiki that tells you what stats mean and what events will unlock which units, and even with that information in hand I understood less than half of what I was doing at any given time. If you know Gundam you have an edge that makes the game playable- knowing how the war is "supposed" to come out gives you a good idea of what you should attack next and who is the most dangerous. (Do NOT let Char Aznable get anywhere near your expensive starships!) But due to the language barrier, you're never 100% sure whether you're making the right move or not. The PSP lets you keep something like 20 separate save files, and I used them all.
Ultimately I did win the war, and enjoyed a small period of relative peace. Which was then obliterated by the Gryps War that forms the basis of Zeta Gundam, the 1985 sequel to the original Gundam series. That's when I called it, because there's just too many variables to keep track of, too many new machines to develop, and it randomly redistributes your forces in peacetime so you have to shuffle everything around to put out fires. I may yet go back to it, though- despite the language barrier the game is engrossing, and without it I'd probably never come up for air.