I don't want to discourage you, but if you're looking to actually understand the stories in some of these Japanese games, you need to come to grips with certain realities, and set realistic goals for yourself.
There are a lot of people, including people majoring in the language at university, who let themselves plateau after memorizing just a few hundred kanji and maybe a couple thousand words. That's not going to do it. You'll understand as much playing a game at that level as you will watching a movie that's only 30% downloaded in bittorrent.
If you're just looking to learn some menu words and be able to recognize when someone tells you to "go east" or "open the door", that's a reasonable and easily accomplished goal. Some people might also find enough reward in understanding whatever bits and pieces of story they get at a low level that that's worth it, too. I never did, though. I majored in Japanese and spent a year abroad in Japan, but I didn't start playing games in Japanese and actually enjoying myself until I passed the JLPT1 a year after I graduated.
You would probably benefit from learning to speak it as well, which is a whole other can of worms, and is something you must develop like any other physically-involved skill: cooking, carpentry, music, sports, surgery, etc. In other words, you need to learn by doing it a lot.
If you really want to learn Japanese, you need to be hardcore. You need to study for a few hours a day, every day, for a few years. It's far from impossible...many have done it, including me, and I'm no prodigy...but know what you're getting into.
Japanese is a deceptive language. In the beginning, you'll see that it doesn't have many irregularities, there are no extensive conjugation/declension tables to memorize like in European languages, and it's actually pretty easy to pronounce. The grammar seems fairly straightforward, too. This is why there are a lot of people out there going around saying "Japanese is easy". You need to ignore them.
When you get into the intermediate level, you'll start to realize what a mountain it really is. In short, you need to learn to think all over again, and your English ability will throw you off more often than it will help you. You also have arguably the most complex writing system in the world to deal with.
Again, I don't want to discourage you. I just want you to know that if you want to really get somewhere, you can't treat this like kiddie swimming lessons, where you do it for an hour or two a week, and sooner or later you're doggie-paddling around wherever you like. You need to attack it like it's K2, and you need to want it like all the freaks who risk life and limb to summit it.