The atmosphere, the music, the graphics, the light its just beautiful one of the few games that mix these things in the right way:
-Unique weaponry and all of them have alternate fire
-Diverse atmosphere and enemies, you will get caught with them in every level, being in the day, noon or night missions
-Simple Objetives, while you can find games that looks like this in Newgrounds, the objetives here are pretty simple: find exit, destroy alien totems, rescue team mates, so nothing its complex or requires luck on achieving things.
-Squash enemies with your awesome spaceboots ;)
-HUD i loved the hud, simple and easy to understand and never mess with your FOV unlike others games (*COUGH* SPIRAL KNIGHTS *COUGH*) also they made it in the right way!, when you get enough damage your HUD display the damage in the screen and still isnt annoying in your FOV and not like others games (*COUGH COUGH* SPIRAL KNIGHTS *COUGH COUGH GOUCH*)
-Story Telling: i like how the game explain the story in every level you complete with images kinda like comic, i just cant wait to get over the next level to see what its going on, it just lovely
-As some other games or like newground games, you have score system that will depend on how you did in the level and the difficulty.
-Probably one of the things that annoyed me was the slippery character that sometimes its kinda hard to land in some places.
-Hook sometimes dont work like you want but once you get the idea on how to control it isnt annoying anymore.
In Short: give a try to this game its really nice and you probably will get caught in the atmosphere of the game and the story as soon you keep advancing trough levels