As i'm a tester again i suppose i'll need to supply feedback. Keep in mind I didn't get far in the Stadia build of HE so if my suggestion is already in it. let me know.
HE demo feels railroaded in terms of secrets at least until you get to level 10 where you can find one blueprint out of the map (sandbox has blueprints yes, but i'm talking story mode). I suggest that in the full game that every other level should encourage players to go out of their way to look around and experiment with their cars. How you may ask? Well perhaps with unlockable side quests and ability to salvage more resources and blueprints off of broken rides and the like. It's not required but exploration should be encouraged to make gameplay easier, or perhaps just give some fun side items for sandbox. Like let's say in one of the neighbor hideouts, you could find a more powerful engine and perhaps some extra parts laying around that Mr. Peterson (and now you) are planning on using. Perhaps you could find one of Mr. Peterson's own blueprints hanging on the wall? It's just an idea.