Because of the palette used to create the bitmapped vehicles and people, they look dark and smudged. Any detail on the models blends into the shadows, making the shadows look larger, not the models look more detailed. The artwork for soldier portraits makes them all look a little goofy, as if they'd just been given laughing gas. Terrain is blocky, conforming to the square grid for movement. There is a utilitarian minimap, a stark, blocky throwback to the days of EGA graphics.
Explosions are dull.
They affect a square area, and each little square within that area gets its own copycat wisp of smoke, making the whole look very artificial. Actually, the physics model for explosions in the X-Com series was quite impressive, even accounting for the direction of the blast, though there were strange artifacts, such as buildings still standing when their lower floors were gone. The sound effects make the graphics look good by comparison. What would normally be a good point turned into this game's most annoying flaw. There is a great deal of dialog for your soldiers and the enemy.