Thank you for your review!
The "Loading..." slide is the animation reset slide which is set to transition after 0 seconds. It was originally blank but I noticed during early testing that the slide doesn't always transition quickly. I added the "Loading..." text to let players know that the game hasn't crashed and that it is literally loading.
You may also be referring to the "Selecting random level" slide. There are actually invisible objects moving around that slide that link to a specific level upon mouse over. In short, the level selected is based on when and where the cursor moves so if the cursor is idle, the slide won't transition.
I also received feedback from friends that the hard levels were very difficult (I've only finished a hard level twice and that's only because I'm very familiar with the animals and I've tested it a lot of times). However, I decided to keep it that way for players who want a challenge.
I will post a devlog on how the game works soon!
P.S. I will check it out when it's released!