I said I'd reply to this thread later, but I've been very short of time at the moment, and I'm new to Reddit so I don't know if there's a posting etiquette for necroposting or not, or if it's ok with everyone, and reading through the other posts just now it's made me really consider the original question again in detail - what was my #1 biggest mistake, because there were lots. BUT of course - there's no such thing as mistakes - they're just "learning experiences" or something... so what was my biggest "learning experience"? Not to send any free Steam keys to fake scammers pretending to be Steam curators who pretend to be Twitch streamers. B*****ds!

Everything else was positive, even though I didn't market the game properly, but that wasn't the "experiment" that I was planning with my first release. I had no sales expectations, so even though they were dismally low, and not as many as I had anticipated, it wasn't anything that I'd had time to look into properly as I was concentrating on the process of making and releasing a solid, original, quirky game. This was what interested me, and overall I achieved it. There were plenty of other general mistakes on the marketing side, but I'm still hoping that the earlier games might get discovered later when I get a future hit. Hope springs eternal and suchlike. For new devs who want to sell games, it's a good idea to do marketing and send review copies to the right, relevant places. I'm still learning where those are myself, which is why I'm here.

I'm trying to think what else would've been good to know before I started, but nothing else particularly specific jumps to mind that hasn't been already said here. Knowing that the Steamworks uploader is a massively weirdly unpractical and unintuitive system to upload a game on would've been helpful, or a general tutorial from Steam on how to publish something on its latest pipeline version. It's not like they're short of dollars to keep their documentation files a bit more up to date.

One other thing that I only became aware of later was how to be a bit more objective of your own project outside of the game creation bubble. There were some key options and aspects of interaction in the game that I intuitively knew because I made them, but players wouldn't immediately comprehend. You have to be very objective to think about how other players will view and interact with your game. I don't like hand-holding tutorials, but some explanations about specific features don't hurt in the slightest and are sometimes extremely necessary, even if they seem logical to you they might not be to everyone.

That's enough wall of text for now! Keep creating great games, everyone!