All subsequent sheets follow a pseudo-random formation, generally moving down the screen but at various speeds and with greatly varying levels of firepower for each individual enemy. This means the strategy must change to looking to find which enemies are descending fastest and picking them off while also trying to break up big groups.
While the aliens from sheet 2 onward look different and are slightly faster than their predecessors, they all move in the same fashion. They are called, in order of appearance, Cyber, Spazmoid, Galactic Hulk, Hep-Hep, Graber, Bum-Fluff, Phantom, Orb and Mega-Bod. Destroying the mothership which appears above the Mega-bods ends the first wave, and starts you again from the beginning (now 'wave 2, sheet 1'), with faster enemies.
This game is notable because of its speed. In particular, the game has probably the fastest player fire-rate of any of the non-scrolling shooters of the period. Most similar games of the time will only let you fire again when the previous laser bolt has either hit an alien or left the screen. Positron has no such limits leading to a much quicker game. It also differs from most such games in that if a life is lost, the sheet begins again regardless of the number of enemies killed. This makes for an infuriating game if the player is killed by the last enemy of the sheet and can lead to effectively repeating the same sheet over until all lives are lost.
The game was also notable for its quick loading time from tape. At under 2 minutes, it was siginificantly lower than most. As a comparison, Acornsoft's Arcadians (a similar but more complex game) takes more than twice as long to load.
The spiritual sequel to Positron, the scrolling shooter Syncron (1987), was also noted for its speed but in that case was criticised as being almost unplayable. Partis himself described it as an exercise in pure speed rather than playability (Micro User magazine, January 1989).