That's a really good game!
1. enemies only start shooting when you perform the very first shot, and the big guy spawns projectiles every time you shoot: nicely done for the consequences theme!!
2. the game has a clear goal (killing all the other bad (bad?) guys) and a manageable learning curve
3. are those really the bad guys? well you're the first one who started shooting
4. visuals, bullets and music - all high quality stuff, also nice that you can turn off the music at a later point if you got bored of the same tune
5. also impressive that you did music/visuals all by yourself, although you used AI assistance for some of the assets
Overall very good job!