The game has potential

First of all, I have to admit that I kind of liked the game. It has a crazy over the top story and it's cool that you've tried to make the gameplay varied. To me it seems that you are pretty clear on what kind of game you want to make, but you don't seem to know how to make it.

My guess is that you were inspired by cheap action/horror movies, and that is a good inspiration. But you need to know what part it is you like about these movies in order to recreate the feeling you want to achieve. For instance, these movies usually have a high pace and a lot of over the top special effects. But in your game, the effects aren't that interesting to look at, and the gameplay is kind of slow. Animation is very important to make the game visually stimulating for the player. Shooting a bug shouldn't just make it disappear with a short animation, it should make the bug splatter and blow up into a pile of flesh and slime. And the bugs could for instance be a lot faster but only take one bullet to kill, which will make the game more suspenseful.

Other general tips when it comes to creating games in GM; don't use built-in message boxes, transitions or particles, never use graphics from photos or other games, and never have an instance where the screen is completely static.

Bottomline, this could easily be a good game, but you need to convince the people playing that every little thing in the game is exactly how you wanted it to be. This game doesn't convince me.