Other than adding background artwork to the play area, everything is downgraded in the SFC version. It's not like many Genesis vs SNES ports where the increase in resolution comes with a big drop in color.
Still shots don't do either game justice, the PCE version is one of the highest quality productions for the system. Everything has nice little effects and animations. The title screen logo has multiple graphic effects each time it comes up, same with the "C 1994 Hudson Soft". The "Bomber" and "Hudson Soft" logos color cycle, the "Push! Run Button" jiggles around, while the background scrolls upward.
After pushing Run, the "letters" all fly across the screen individually. As you navigate between screens, they all rearrange and icons slide on and off the screen. In both versions the little Bomberman heads look around and react to the action.
Here are some shots from the
arcade/Neo Geo version matched to the PCE version-
The "Continue?" logo in the PCE version color cycles. The Neo Geo version's music sounds similar to PCE PSG which is pretty cool.