Reached level 28 in this challenging game, But... I ran out of lives to continue further. This game is often played better with a friend who controls firing or using the Robotron controller purchased from ebay.
Alright! It was tough as I had a hunter alien on my heels the whole time, but I was able to reach Nicole, who was attached to the Marker. I defeated her (eventually) and made my escape with Ellie. What a cool game. Final boss and game ending! Great stream!