Charming game with a great soundtrack and nice visuals! I'll answer your questions directly.
Was the core card-stacking loop easy to understand? I found it pretty straightforward. You have a "cookbook" and a "formula" for everything, and you just stack all the cards you need into one pot. The guide/tutorial also helped with the prioritization of what to build next, but the combat element soon got in the way of me following the list. I got all the way to exploring the cave and forest, but I had to stop and get busy making more villagers to fight/do stuff. If you think the tutorial is important to follow through, it might be a good idea to slow down the escalation until the tutorial is over.
Did the game ever feel overwhelming or unclear? I am not 100% sure I understand the combat mechanics properly just yet. In my last day, I was going to fight some tigers I think. My guys were on their way to intercept them on the road, but when the day ended, all my villagers suddenly just died, then the guys on the road died, and that was that. Do you maybe need to reach the enemy base by the end of the day? If not, then I am not sure what happened as I never saw the tigers. I expected the mobs to start on their way towards my castle like an old school tower defense game and for my fighters to meet them halfway. Anyway... I probably wouldn't have survived the fight either way, as a pop-up decision I made turned sour and I lost all my villagers except for 2, haha! That felt quite drastic at a point where the enemies are much stronger, so the fight was already lost. But maybe that's just something you have to learn throughout multiple gameplays.
How many days did you survive on your first run, and did you feel like starting another? I got to day 7 I think. When the tigers attack. And I definitely had fun and would play again! Honestly, this isn't really a genre I play a lot, but I still had fun. I think people who regularly play this genre will have a blast with your game.
Cheers!