This is superb! The graphics are great, the dialog is well-written, the game runs very smoothly, and I love the swinging rope physics. The stomp effects are pretty awesome too.
I love the dackpaws, too. Their animations have a lot of character, and their sound effects are perfect. The giant fish is pretty awesome too, though I'd like it better if it had sound effects. Wait, I just noticed the chomping sound--it's very subtle. Maybe add in some kind of monstrous groaning noise?
I also like how you unexpectedly add in a partner mechanic midway through the game. It helps keep it fresh.
Here's my critical feedback:
With some of the multi-level buildings in the tutorial area, if you're on top of a lower roof on the side of a building, you can easily walk directly through the building and fall off when you're intending to simply jump to a higher-level roof. (If that makes any sense.) It looks like you fixed this in the area with the elevator, though, so it appears to be a level design problem rather than an engine problem.
I got through the plasma facility without too much difficulty, but it's a weird decision to have an area filled with so many insta-death traps at the very beginning of the game.
The quarry, by comparison, is much more forgiving. The second part of it, though...um...why on earth would they stick exposed plasma coils in the middle of an elevator shaft so that the person riding the elevator is incredibly likely to die? It hurts the believability of the area. I mean, I thought it was going a little overboard in the plasma factory, but this just screams "the game designer thought it would be cool."
Same thing for the area of the forest with freaking plasma beams coming out of the trees. I would try to think of more environment-appropriate traps, like the rocks in the quarry.
With the turning switches, it would be good if there were some more pronounced audio feedback to let me know when I'm reaching the end so that I don't overshoot and have to wait for it to retract and then go through the whole process again.
On the whole, though, the game is really very well-done!