I really like the concept of the grappling hook, however there were a few problems.
The grappling hook was really buggy and I couldn't play the game as intended due to this. Sometimes it would barely move, sometimes it would hook on the air, and sometimes it would fly to the stratosphere and hook on the ceiling. These can definitely be fixed, and I'm so sorry that you couldn't fix these issues due to time constraints.
The environment is very good, and the graphics are nice. The music is also quite nice too, good job!
Overall, a game that suffers from bugs on its core mechanic. The polishing is done really well though, good job!