First game I managed to develop from start to finish. This was done in 2007 towards the end of my study days, using Flash/ActionScript 2.0 and compiled into .exe using Zinc. It's a simple sidescroller game where you control a helicopter named "Hellcopter" that needs to shoot and save the city from alien invaders. Watch out to not crash to the ground or get hit by aliens.
Executable for Windows still exists here: https://sample.easwee.net/hellcopter-operation/hellcopter-operation-v1.zip