Stage 2 : Instructions on what changes to make on existing code: (Make sure you don’t change the existing code at all, preserve the existing behavior) • Aliens are initially laid out as a sequence according to the configuration file. Aliens have a bitmaps and a position. • Aliens must have different bitmaps. • Aliens have the ability to shoot the space ship. The shooting happens periodically. The beam travels vertically. • When the space ship hits an alien, it disappears; a displayed score counter is incremented. • When a beam of an alien hits the space ship, the game stops. • Aliens are actively hunting the spaceship What’s required: One to two A4 pages typed review of the code you received in PDF. Things need to consider: • it must compile and run on the lab machines (QT Compiler/platform only, no visual studio); • The previous behaviour must be preserved; • appropriate use of a structural design pattern for game, aliens, beams are used. • it must correctly use the configuration file to play the game. • crash safety: the program will not crash given invalid configuration files; 15 marks are attributed to the following • clear code using meaningful variable and method names as well as informative commenting and documentation; • aliens can be grouped into swarms and show a single behaviour • the configuration file can deal with swarms of aliens 10 marks are attributed to the following • Aliens can move in a periodic fashion in a fixed trajectory. • The aliens trajectory is encoded in the configuration file. 25 marks are attributed to sophisticated extensions. Some suggestions are listed below,