Since uploading the game, I've received a lot of feedback. Although I hadn't planned on making an update, I think it’s worthwhile to implement some bug fixes and improve performance by letting players choose graphic settings. So, I chose a nice free asset from Fab for the settings menu:

and got assistance from the Defender template team. 

Here’s the modification I made to the behavior tree. It was a bit tricky to pinpoint, but I figured it out.

I also optimised the last level because it was really heavy. The main reason was the number of lights. You see I do dynamic lighting and not baked.

The new version will be uploaded soon. 

Thank you all for your support. 

I wish more people were playing the game, but I suppose that's how it goes.