Heap Software Engineer interview questions

I applied through AngelList. There was a phone screen with a recruiter, a 2hr HackerRank coding challenge, a technical video call with an engineer, and an all day coding challenge for the final round. I had a great experience with the phone/video calls, and the HankerRank coding challenge was fine. I think I understand the motivation for the all day assessment (as they describe it in a blog post), but to me it seems a little too much to ask on top of the other interview phases. It's unclear to me whether or not the assignment is intended to be completable in the allotted time. I neither completed it entirely nor received an offer so it's very possible that it is. Either way, it's pretty stressful and emotionally taxing to be coding all day with a job on the line. I think this segment might be improved by shortening it to about half the time it is now and simplifying it a bit. It's also a bit frustrating to get "you checked off a lot of boxes for the role" as the only feedback after sinking ~11 hours of work into interviewing in total. Even something vague like "you didn't complete enough of the assessment" or "your oral communication skills were lacking" would be nice.