Agony

Agony is a surreal-fantasy side-scrolling shoot 'em up, created by Psygnosis in 1992 for the Amiga. The game has never been released on other platforms. The main character is an owl (the company logo) flying through six worlds filled with monsters; the owl fires at the enemies with various echolocation waves. The game demonstrated the Amiga graphics features obtained with advanced techniques, including scales of colors done with raster lines, halfbrite graphics mode, three layers of parallax scrolling, in-game palette swapping, and continuous flashing the background palette to simulate additional colors.