Thank you for playing our game and for your feedback. We're glad you liked it.
Answering most of your points will come down to the fact that it's a ludum dare jam game, made in 3 days, so we weren't able to finish everything to our liking. That's our excuse :)
Seeing how it's a jam game, I don't think we're going to update it, other than bug fixes and quality of life improvements. In our heads, it's a finished product displaying what we're capable of making in a short amount of time. But, I do have plans on making a game based around similar mechanics.
Unfortunately, we weren't able to put in a tutorial in the game resulting in a lot of players not figuring out mechanics that are core to fully enjoying it.
The slide mechanic that you found and were confused about is our substitute for sprinting, as you can slide jump, gaining momentum this way. You also can wall jump and chain wall jumps and slide jumps one after another to traverse the space. It's required for obtaining some of the treasures and stamina bonus potions.
That's about it, thanks again, seeing people even outside of jam space enjoying our work is an amazing feeling.