Looks like I was relatively fast compared to other completions

Nice and funny game
To answer your concerns:
1) Yes, a lot of people (~30-60%) spam-comment. You can often find this out by going to commenters' profile and see times/intervals at which they post comments. Some people comment on different games as often as every 1-3 minutes, which obviously means they haven't played
2) There are two types of ratings: game rating (general ones - a single 1-5 star) and jam ratings (jam specific - several categories, 1-5 star each). Your analytics page likely shows general Itch rating.
Yes, there are jams you want to grind, but for this one I chose to make a small highly polished game and have fun!
Regarding winning, it's hard to reason about "fairness" with certainty, because public vote is highly random - look at the public vote winners from Brackeys 2021.2:) I'd say exchanging 5-star ratings would be unfair, though
Here is how it works:
The game: https://nns2009.itch.io/subscribe
Actually, playing it is not necessary, you can just skip playing and rate it 5 stars straight away - that is ok as well
Thanks for trying out!
As I was doing it for a short game jam and I happened to be busy part of the time, my main problem was to at least finish the main loop (buy seed, plant, extract, sell crop) somehow, which I barely managed to do.
But then - yes, I know it's overwhelming. Tutorial and incremental progression is critically missing. Ideally, it would start with only ~5 lines of boilerplate code that you'll expand yourself.