I've been using the Deep Dive feature for the past few weeks and it's genuinely helpful for identifying weak spots. One thing that would make it even better: progress tracking across multiple levels.
Right now, if I take N4 and N3 Deep Dives, I can't easily see how my performance compares between them. Being able to visualize improvement (or identify consistent weak areas) as you move up would be really useful for planning study focus.
Not urgent, but something to consider for future updates.