I just played and finished BRS: The Game for PSP. And just giving my thoughts. The game is coming to US in English by NIS America so you can wait it out till then.
Story wise the game has no relation to the OVA.
The game progresses through short missions through 6 stages. There is an extra hunting mission at the end of each stage where you progress through the entire stage to the boss with only 2 healing points (if you found them during the missions). Otherwise you have to rely on your items.
Gameplay wise, you mainly go from point A to point B. One area has you controlling a bike where you weave through enemies. In battle, you control BRS's gun to lock on targets and fire. Depending on your heat gague, is the number shots you fire. Blue (0-20%-ish) I think you shoot like 4 and as your weapon heat increases, the number decrease. Reaching 100% will cause you to overheat, leaving you unable to control (except items) and vulnerable. Items can be used anytime (as long not getting stunned) and you can carry only a max of 5 per item. Items is pretty much you main healing. You also have a choice of 4 skills and after use have a recharge of about 20 to 60 seconds depending on the skill. You can guard to lower damage but doing so will keep your heat % so you can't cool down so you should only block when necessary. You can dodge at a cost of 10% heat (I believe), however you only have two positions to move around. Timing is critical in a dodge. Most enemies when they are about to attack flash and powerful attacks they charge. While targeting is usually easy as it locks on, later enemies dash around preventing a lock and may enable an ability to prevent a lock. Enemies are fairly easy and predicable. Bosses however are a challenge.
Skills (offensive, defensive and passive) are obtained by completing records. Most of these will be obtained normally as you progress through the game as it requires just defeating certain enemies. Some require defeating enemies with a certain skill. And some require, certain tasks like completing the bike areas with no damage. As you can only bring 4 offensive and defensive skills in battle, even though there is a variety of skills, mostly you will bring the same skills through the game. Like the sniper skill stuns but is useless in a boss battle in my opinion. The vulcan cannon shoots like a machine gun but you will be vulnerable throughout the attack. And too many defensive skills is not really good as you will be relying on the normal cannon (which you should keep your heat guage free for dodging).
There is really not much an equipment system like RPGs. You get better weapons by story. And costumes by records.
The game seems to be able to be completed by just going through all the missions straight (but would be a great challenge). Going back missions would be necessary to refill items and leveling up will definitely make it easier.
Like Criminal Girls, the game is fairly easy and simple. I think the game doesn't really pick up till half way. Story is pretty much the main reason to continue as normal battles are easy and repetitive and the game is pretty much linear.
