GunBlaze S is a remake of GunBlaze.
The story remains the same as in the original game, and the dialogues almost the same, with a few minor omissions. The gameplay is also largely unchanged.
The main difference between the two versions is in the graphics. Many locations and cut scenes in GunBlaze S were re-drawn from scratch. Some of the locations have different layout. Generally, the graphics are clearly more detailed, even though they retain the simple 2D top-down style of the original. There are voice-overs for all story-related dialogues in this version.
There is also another significant change: the original GunBlaze had scenes with nudity; GunBlaze S has none. The sexual innuendo is present in the dialogues, and there are scenes with scantily clad young girls; but the adult content is gone.