Originally, the character should move at the same speed in both dimensions (which is quite fast), from what I understand the original dimension is slowed down by the amount of objects (bad optimization) or is this a quote of taste and the character is too slow for you?
And it's nice that you like the story :)
I wasn't sure if moving slowly was an intentional choice or a technical limitation. Glad it's the later; when there is a lot to explore I like to be able to experiment quickly by moving around a lot, the faster the better.
I was super intrigued by the dog bitting me in the alternate dimension, and that kept me going to figure the mystery out.
One small suggestion: it took me a while to realize which key to use to sit the dog (for some reason I didn't immediately recognize the space symbol even though I'm a programmer, that's embarrassing ahaha) so I would encourage you to spell out "Space" in letters instead so it's more accessible.
