Space! by ignacobo

Program
-------
Space!
by @ignacobo
Load and Run
------------
On any ZXSpectrum 48kb emulator,
open .TAP file and input RUN +enter
Controls
--------
    O    Left
    P     Right
Space     Laser
Mission
-------
Your goal is to terminate all the enemies Spaceships that are trying to invade your galaxy. Watch out with the MotherShip!
Your mission fails if any of the enemies reaches your level.
Brief listing explanation
-------------------------
All 10 lines are 120 characters long, or less.
Data structures and User Defined Graphics read from data Strings to save characters. (Lines 0, 1 and 2).
Star field is created using LPrint pointing to Video Memory (Line 2).
Pixel-by-Pixel vertical scroll in Basic, achieved moving Video Memory data using DefAdd trick (Line 3).
End-Of-Game detection peeking control byte on base level. (Line 4).
Random position enemy creation. (Line 5).
Keyboard detection reading ports with IN function. (Line 6).
Hero Spaceship moving left and right within screen borders, drawing and erasing using Over 1 mode.  (Line 7).
Searching for enemy-in-sight above hero ship. (Line 8).
Laser effect created with Draw command and Over 1 mode. (Line 9).