Here is the full list of all 34 Voidrun achievements.
Kill 20x flames
Kill 100x droids and/or sentinels
Kill 200x worms
score 2000 or more in arcade mode
score 5000 or more in arcade mode
score 10000 or more in arcade mode
Destroy the giant tree Methuselah
Destroy the Void Maw
Kill 4+ monster with self-destruct
Reach 72 Void Balls
Finish the classic mode ( any difficulty )
Finish the classic mode with hard difficulty
Finish the classic mode with nightmare difficulty
Disobey an order
Finishing every planet without any lost ship
Beat Omessah in classic mode
Beat Girold Belt in classic mode
Beat Sagoroth in classic mode
Beat Yareal in classic mode
Beat Korbulys in classic mode
Beat Alkeer in classic mode
Beat Hermes Station in classic mode
Beat Zeth Core in classic mode
Beat Nusteria in classic mode
Finish the classic mode with the standard ship ( hard difficulty or higher )
Finish the classic mode with the berserk ship ( hard difficulty or higher )
Finish the classic mode with the scout ship ( hard difficulty or higher )
Finish the classic mode with the dancer ship ( hard difficulty or higher )
Finish the classic mode with the shaker ship ( hard difficulty or higher )
Finish the classic mode with the storm ship ( hard difficulty or higher )
Finish the classic mode with the snake ship ( hard difficulty or higher )
Finish the classic mode with the tank ship ( hard difficulty or higher )
Finish the classic mode with the impact ship ( hard difficulty or higher )
Finish the classic mode with the fantom ship ( hard difficulty or higher )