Thanks! I spent a lot of time designing the environment, and the grapple gun was by far the hardest thing to implement. I'm glad you liked it.
I intentionally made the level seem like a maze to cover the fact that it's actually quite small, but that's definitely an important feedback to consider.
There is a sidearm you can find by going through the vent found in the main room (on the same wall as the exit). I'm glad you were able to beat the game without it though! It was always intended to be optional.