Halloween Harry (Alien Carnage) (Dos game 1993) 

Halloween Harry or Alien Carnage is a typical side-scrolling platform game made by SubZero Software published by Apogee Software.
It has 4 episodes (mission).
Unluckily, because of demo version, I can play only 1 mission, called 'office block'.
The game rule is that you ought to rescue everybody.
You can fly and buy diverse weapons in vending machines during playing the game.