Fun concept! However there are some issues that come with the submission.
During the "level complete" screen many objects hide the button to proceed to the next level, making it difficult to press.
Sometimes mario will get stuck on corners trying to chase you, this is very rare, but did ruin some of the later levels difficulty.
the overall presentation is very amateur ish. using the NES Super Mario Bros sprites is fine, however using stock Godot UI nodes for buttons, with a simple gray background makes the game really unappealing to look at.
The game however is a cool idea! I like the concept of having the stealth around Mario at times, and some chases can get quite intense! You have a good future in games development ahead if you carry on improving and learning!