Was able to design a new step 3 I'm happy with:
https://i.gyazo.com/3f451e6252dec208513b909c650bd81b.png
And adjusted the final step as a result:
https://i.gyazo.com/a60f11e13a3e1e56f5080b0e40102bc3.png
Basically tried to design it so after destroying the arrows, move the fixation off that while giving players a chance to get more familiar with how the blocks move around with a more finite goal. Before the final step which is a bit looser, where they should hopefully be more comfortable after completing a specific goal, and thinking more broadly about how to approach lowering their score.
Also it allows the introduction of the score estimate, and final score calculation separately, to reduce the number of elements showing up at each stage.
Hope you think this would have helped you?
