Good question! The short answer to this is yes, if you want the paid version of each update, you'll need to pay for each updated version. However, if you're a Recurring Supporter on our Patreon site, you get the latest demo builds for free 1 week ahead of the public release!
I'm sorry but that is a very poorly thought out idea. I've already paid $18 for this and you want me to pay $10 or more for every time this game is updated in addition to the pay you already get on patreon on a monthly basis. And that is for just a demo, not even updates to a fully completed game. If 1.0.0 is the full release and you plan on keeping the price of the demo at $10 then by the time the full game releases a person would have needed to pay $68, if not more if you plan on increasing the price on the demos going forwards. For that price I could buy a full game on Steam or even several. And to the point that no doubt people will want to bring up of "Well just wait for the full finished game and buy that." that is a valid idea however the lack of consistent updates, even just on progress, leads people to want to access the game in the event that the creator loses interest or has issues during production and possibly removes the game from the site, the former part of this occurring quite often.
A distinction I'd like to point out is that there is a free version of the demo and a paid version of the demo—both versions have updates, buying the paid version just gets you some additional content that isn't in the free version. So you won't necessarily need to spend $8 every time there's an update, unless you want to get that extra content. If you don't want to pay the $8 for the paid version of the update, that's ok, the free version has plenty of updated content in it, too. I also currently have no plans to raise the price of the paid versions of the demos in the future, although a change like that will be communicated ahead of time if that were to happen.
That being said, a model that I'm curious to get your opinion on would be paying a single upfront fee for ongoing access to the paid version, with free updates rolled out/patched for each demo release (like paying for the "premium" version of the game at first, and then getting that "premium" DLC content for free)? I'm not sure what that initial upfront cost would be, as I'm currently brainstorming and don't have anything concrete nailed down, but would a model like that be more palatable? Because I do concede your point, that paying a total of $60+ for multiple demo versions before the final game is ready for release is a steep ask. I'd be remiss if I didn't note that those payments are going directly to supporting the development of this project (and I want to extend another giant thank you to everyone who has bought the paid version of the demo, we do sincerely appreciate your financial support!), but at the same time, I do also genuinely want to find a way to make this economical for you all as the players/consumers as well as us as the developers; it's about finding that balance, and I do see it's not an ideal model as it currently stands. I'm also very open to other helpful suggestions you may have—I'll fully admit to not being exactly business-savvy in areas like this, and I'm still learning those particular ropes in the course of working on this project. This is my first rodeo in this kind of work, so any constructive advice you (or anyone else) have would be greatly appreciated! Thanks!
All good points however usually with the free version on the update all of the content previously locked behind the paid version is then added to the following free version in the next update. So as an example all of the paid content in 04 would then be free in 0.5. This is pretty much the standard has how to most creators use paid demos or updates involving Patreon. Beyond this another reason people are disliking this payment plan about paying for each demo is that you do have a Patreon, one where you are already having people pay in order to access the game early. While I could be wrong I haven't seen a single other creator with one also have paid demos, at most they have a one time payment to access the game or have the non patreon version free but locked to one update behind the patreon, sort of an incentive to join.
So to answer your question there's three possible methods you might want to consider (though other users might suggest others):
1. Stagger the updates so the patreon has access one month in advance of all other sites. This will incentivize people to join the patreon in order to access the game early.
2. Have people pay $10-20 for access to all paid demos but also include the staggering idea in option one to further entice potential buyers while also giving another option on how to access the game.
3. Have people pay $30~ upfront but also give them the full game for free upon release as an incentive for them to buy it early. (Allowing people access to the final version for free would also be an amazing offer for higher tier patreons as it is once again another incentive for them to give money on a monthly basis versus a one time fee)
You've given me a lot of good stuff to think about, and I appreciate you taking the time to explain the rationale and propose some potential alternatives here! I can see how these options make sense and would be a lot more sustainable/better value compared to the current model I'm using, and I want to just say thanks for helping me course correct. I'll be taking steps to implement some version of this for the next release (need to figure out the logistics of making it all work based on the platforms in play, plus I'll be soliciting feedback on strategy before implementing, so stay tuned for updates), and I hope doing so makes this a better experience from a buy-in/supporter perspective.