How's Image Fight II? Still playable today? (Are the production values close to the Soldier games, for instance?)
Production values are high, sure, though I'd still call Super Star Soldier the better game.
I agree with o.pwuaioc, SSS is superior game: more accessible, more variety, more "freedom" to approach game using a wide variety of techniques. SSS is easy, at least for me, except for a few moments of stress. I may be jaded because I played the heck out of this game.
Image Fight II is a challenging game that is more about "surviving"...you are not going to worry about your score, or trying to destroy every single enemy on the screen, because you are solely concentrated on devising a feasible strategy for getting through the stage.
It's a good game, especially if you are a shootemup fan, but casual gamers may find it intimidating (R-Type ramps up difficulty, too, and probably scares off casual gamers).