The player controls a surface rover vehicle to enter several "rifts" on an alien planet which are effectively fractal mazes. A lost civilisation known as the Ancients has left strange machinery, so-called "hulks", within these rifts which are guarded by armed flying saucers of different design and color. Depending on their respective color, shields and gunshots of both the rover and the saucers are of varying effectiveness against each other; part of the game is figuring out which shield and weapon modules work best where. By means of a drone robot, the rover can retrieve modules with various functions from nearby hulks. It can only be deployed when all attacking Guardian Saucers have been destroyed. The modules can then be installed in the rover, analyzed aboard the player's space ship, or sold; the rover can carry up to six different modules at a time which can be activated and de-activated as the player sees fit. A large variety of modules is available: Different weapon and shield modules with varying power levels and color codes, modules that increase the rover's power output, a mapper, and even one module that turns the retrieval probe into a bomb, destroying any hulks the probe is sent to investigate instead of retrieving modules. Conversely, different types of hulks exist including one that simply "swallows" the probe without yielding a module, requiring the player to purchase a new probe. The goal of the game is to find and destroy the saucer control base hulk which is located in the 20th rift. To this end, the player must explore the rifts, find hulks, retrieve and analyze modules and understand the color-coding of weapons and shields to overcome the increasingly aggressive and dangerous saucers. The game can be solved in several ways; the quickest is to acquire the bomb module and send the probe into the saucer base with the bomb module activated.
Reception
Info rated Koronis Rift four stars out of five, stating that it was the best of Epyx's four Lucasfilm games. Computer Gaming World stated that "if KR is a game, it is also a puzzle... arcade skill alone isn't enough". The reviewer did not enjoy the game because it was so difficult that he spent too much time savescumming, but praised the graphics and sound. Zzap!64 thought that the game was an improvement on its predecessor, Rescue on Fractalus, with superior graphics and gameplay. It was given an overall rating of 96%.
