Big differences between "electric" and "acoustic" amps are going to be in the tone controls and speakers.
"Electric" amps combine with the instrument to create the player's sound. These amps have tone controls and speakers that are configured to give emphasis to certain frequency ranges that have been found to be quite pleasing to most players, coloring the sound of the instrument. This is generally some bass boost, mid cut and treble boost. If the amp's frequency response is displayed graphically it will resemble a letter V. The amps are not flat in their frequency response. (The bass and the amp together make a complete instrument. Without one or the other you will not achieve the sound you desire.)
"Acoustic" amps resemble dedicated PA systems. These amps do not color the sound of the instrument, they simply make it louder. If their tone controls are set "flat" then the amp's frequency response is much more likely to be flat. The amp's response is transparent to the sound of the instrument. (If you boost the bass, cut the mid and boost the treble controls it will move these amps in the direction of "electric" amps. The bass has the desired sound on its own which won't change when it is amplified.)
