I love that the story, the "enter a bunker and steal stuff" part, is just a tutorial for the boss fight :D
Beautiful pixel art. The sound effects really make the guns, bombs and laser feel like a real threat.
I've played enough games to know that a barrel with a flame symbol on it means "boom", so I had no problem understanding what to do once I got to the boss. The difficulty was good for a game jam, but could probably be ramped up if you continue working on this. The laser beam was really the only weapon that could score a hit, if you were carrying a barrel.
Good job!