FireMadness is a top-down bullet hell shooter inspired by CrossFire game (1981 by Jay Sullivan) written in Castle Game Engine (Lazarus / Free Pascal)

The goal of the game is to eliminate all enemy bots. Use arrow keys to move and WASD to fire at 4 directions (hold down the button for rapid fire). Player has 200 HP until death... and that's not much...
You can move only vertical or horizontal direction at the same time, and movement automatically stops at crossroads (you can invert the movement direction).
Enemies come in groups of 3+ starting from lazy easy form, after destroyed they transform in more healthy and powerful medium form and finally into tough, quick and rapid-firing hard form.  Occasionaly hard form after being destroyed transforms into boss form (the name says it all).

No installation is required, just extract all files to one folder and play.
You may need to set "executable" bit in Linux.

Linux version requires 32bit GTK+2
(Debian/Ubuntu package reference):
libopenal1
libpng
zlib1g
libvorbis
libfreetype6
libgtkglext1