I just sent in my entry to the 7DRL, declaring my success! There's always things that could be improved upon, but all in all I'm quite happy with the result. It's a take on Vampire Survivors but with a turn-based twist.
https://ptrefall.itch.io/horde-survivors
From day 1 I focused hard on the core mechanics and wanted to nail turn based movement, while supporting physics based movement, and this was a challenge that required a few iterations to somewhat get right (there's still room for improvement).
By Day 3 I had already run through probably 5 rewrites of the movement system, and it still wasn't very pleasant. But I also had focused on item pickups, XP and hoard spawning, though everything was still very crude.
By Day 6 I had the full game loop implemented with turn and death count, main menu, simple character selection, level ups and had put in some fun traps on the level that could have potential to be part of the meta to win the game. I had finally found an approach to the movement system that was "passable", and though it saw some minor tweaks the last day, it was pretty much set.