I'm happy you enjoyed playing my game. I'm going to send you a screenshot of the GBStudio platformer settings I used on Twitter. The basic idea is to set the minimum and walk velocity to the same value and a high deceleration. Because I'm generally bad at playing platformers I don't like it when the player builds up speed and thus needs some time to stop after you've released the button. It adds an extra layer of difficulty for me.
The player sprite is 8x8 pixels. I made it so small to have enough space to work with for my single screen levels without scrolling.
You can listen to my original song in the game. Just press Select on the title screen to choose between Tronimal's remix and my original song.