Raiden is much heavier on bullets than most of its 16-bit peers, and it bears a greater resemblance in play style to the manic shooters that came after it than it does to the titles that sat alongside it on store shelves. The formula will feel familiar to bullet-hell vets: make do with your regular guns while taking care of small-fry, and save your bombs for times when you absolutely need them (namely, when something huge comes along and is about to fill the screen with speedy projectiles). You have to use a little strategy and memorize the ways in which the tougher sequences play out. Raiden certainly isn't as wild as many of its descendents, but it's hard and will seem especially so to those "aces" who earned their titles breezing through Compile blasters and the like. For a wretchedly ancient shooter, Raiden is strikingly modern in some respects.
It's also an absolute bore visually. There's a lot of dirt, water, and base-type area to fly over, and things become even more revolting when you soar up into space, where even the asteroids are ugly. Block-shaped tanks and cookie-cutter craft, no matter how large they are or how many bullets they fire, aren't all that much fun to fight, especially over the course of what's a pretty long adventure at eight levels.
It's Raiden's strange lot to be action packed but dull. I'd like to be able to say that being hard and standing out stylistically among Turbo shooters are factors that make it worth playing. However, Tatsujin is rougher and better, and Kyuukyoku Tiger is similar in theme and gameplay style but manages to be a lot more enjoyable. But Raiden is still decent, and if you've tackled those two (along with the many other Gunheds and Soldier Blades that rank higher in PCE shoot 'em up hierarchy) and you're seeking a new challenge, well, here you go.
Raiden doesn't hesitate to let you know exactly what you're in for: lots of bullets and very dull enemies and environments.
All right, here's an enemy I like. The trains that come chugging along in Level 2 are my favorite Raiden foes.
You have only two primary weapons: a spreading vulcan and a concentrated laser. Typical positives and negatives apply.