Batsugun is generally considered to be one of the first “manic” shmups. All that really means is that it was the first throw a whole fuckload of bullets at you. That alone makes it worth mentioning, but it also has an experience system, that I’ve only seen in a few other games since.
As you progress, you earn experience points, and can level up your ship. With every level, you’ll get an extra bomb and a shield that allows you to be hit once without losing a life (and your experience points). With experience points also come point multipliers.
It’s also one of the first games that featured a reduced hitbox, a term you’re probably already familiar with if you play FPS games, or know what the words “hit” and “box” mean, but put simply: the part of your ship that can be hit by bullets. In a manic shooter, there are likely to be moments where there just isn’t space for your entire ship to come through unscathed, which means allowances need to be made. So what shmup makers started doing is reducing the area of your ship that can actually be damaged to an area only a few pixels square (generally between 5 and 3). It probably sounds a little silly, but if you find yourself playing manic shmups a lot, you’ll be grateful for the innovation.
The game itself isn’t especially interesting, but it’s worth noting simply for its innovations, and the fact that it was one of the first manic shooters.
I’m not going to get to bogged down in developers and publishers and whatnot here, but it’s worth noting that the game’s developers, Toaplan, went bankrupt soon after the release of this game. Draw your own conclusions from that. Fortunately, most of the employees went on to bigger and better things.