While the ghost can be useful, it can become quite annoying while running. Here's a guide explaining how to get rid of it until you beat your best time and have to repeat the process. For the moment this is the only solution I found.

First of all, open your game directory

and open the "save-file.cfg" file, using a text editor.

Here you'll have to modify the "ghost_array_size" line, and set it to 0, like I show on the image above. In this example, the ghost for level 1 will not be displayed.

Repeat the process for other levels, modifying the ghost_array_size parameter in [levelXghost_array_size], X being the number of the level.