Wow, nice little game here.
> The title screen is well done, clean, neat, you immediately want to launch the game.
> The game is well polished : the screen that shakes when you attack, the particles, the sound effects, the ground that gets stained when you kill an enemy... All these little details are very important and contribute to make the user experience very pleasant.
> Colors that change each time you restart a game, it's great, it avoids too much repetition.
> There's one thing I didn't understand : how to switch between grappling hook and gun? I felt like I couldn't really control the action I wanted to do.
> Ideas for improvements : more musics, maybe more weapons, a shop...
> I think the game's a little too hard : we're running out of time too fast, and the enemies are hurting a little too much. Or maybe I'm the one who really sucks ahah Anyway, to improve this, I have a few suggestions : set the time back to maximum when you go to the next level, or make the enemies sometimes drop an item that add time.
Anyway, I really enjoyed this little game, good job =D