I like the idea, but the execution leaves a lot to be desired. The basic platformer controls feel pretty good at least (decent movement speed, jump height and gravity plus no collision issues), though it would be nice if the jump height depended on how long the button is held. Unfortunately, the rest of the mechanics feel quite buggy. It's a shame because a grapple arm sounds like it could be fun.

Not much to say about the graphics; they're about as basic as you can get. The sound effects are decent (aside from the repeating sound when your arm hits a wall). I really enjoyed the music though. It's probably the best part about the game.

Got stuck at the level 2 exit as well. Like the soundtrack. But shooting the arm into a block sounds bad (infinite loop? Make sure you check the sound isn't already playing before playing it again). Also, wasn't sure how to use the grapple-hook feature you mention.

The game crashed in the 3rd room (the one where you have to shoot one guy from above) as I was unable to get to the next level and I didn't feel like trying again :T

The idea of shooting a bionic arm is good (was super fun in Metal Gear Solid V), and I was surprised by how tight the basic collisions for moving and jumping was, so good job on that! I also like the music track, it gives off a nice retro steampunk vibe.

As KilvenDeneras mentioned the third level doesn't work. I didn't have too much trouble aiming as he did though, except when you reach the end of the second level your character starts aiming upward and it won't control correctly.

It seems like getting the basic engine down took most of your time, so you might consider developing a simpler engine for your next game jam so you have more time to develop the ideas, mechanics, and concepts.

Alright, I went in to try out your game and looks like it'll only go as far as level 2.

When I reach the door in the second level, attempting to interact with it gives this error

FATAL ERROR in
action number 1
of  Step Event0
for object obj_flier:

Variable obj_flier.moveup(100016, 
-2147483648) not set before reading it.
at gml_Object_obj_flier_Step_0

Thought I'd share it with you, just to make sure you see it.

One thing I would have tried to get tighter would be how the mouse position affects your aim. It seemed the arm lags behind the movement of the cursor. Made it a bit difficult to control initially.