Thanks for trying out the game.
The early levels are pretty much just a tutorial so they are a bit slow but I'm sorta working on a way to make them more interesting. It's not like you have to play them again if I update the game because old saves will work on newer versions.
You can also toggle the game's speed up or down by pressing E and Q respectively. The functionality is there, I just haven't found a place to put it in the UI.