Obviously there is going to be a difference in graphics, due to the majority of the Vectrex version being in vector (the original was in raster) and the robots look like octopuses, plus there is no visible change indicating the robots' difficulty level has increased since the Vectrex doesn't have color. The difficulty level in this port also isn't as high, due to the robots not being as aggressive as on the arcade original, the player can shoot several more shots at a time and the players' and robots' shots do not cancel each other out (although arguably this could make the game more difficult, depending on a person's opinion).
Evil Otto also makes a bouncing noise as he travels, which was not included in the original, plus the player's shots will now pass through him; originally he could be shot (although not killed).
There is also no voice synthesis in this version, there are fewer mazes, an extra life is awarded at 5,000 points, which on the original it was 7,000 (although that could be changed depending on the arcade operator's choosing), and robots can, at times, either partially walk through a wall segment until they get destroyed, or can totally pass through them unharmed.
This port had a few bugs, one of which caused a glitch with the score, where it would be replaced by a dash and a graphic that looks like a car; when the game ended, the player would find a very high score (usually in the 100,000 range) that they did not achieve. Also, at times the player would either not be awarded a bonus for shooting all robots in a maze and/or the text stating the bonus would not appear.
A Berzerk Debugged prototype was released with bug fixes.
[EU] [UK] "Berzerk [Model 8123]