It is hard to explain all these concepts and at the same time, create a whole game without using lot of words and pages. I wish I had more space to show you more about particle systems and UI; however, at the same time, I hope you correctly understood all the steps of this chapter and are now able to create your own particle system, choosing between different modules and achieving the result that you have in your mind.
As usual, here is some homework for you:
Spot the missing behavior: You should notice that there is something missing when you play the game. We created the fuel variable and the code that handles it; however, we never actually implemented its usage in the game. The fix is pretty easy; check Flying Pawn, the nodes needed are an AND boolean and a branch.
More time: Instead of increasing the energy, try to change the behavior of the collectable item to add a little bit of time (or both energy and time) when one of them is collected.
A game over UI: Try to create a new...