I see what you mean regarding the 10€ tier. I don't think I've ever really noticed anyone referring to Euro's as 'bucks', so my mind immediately thought 'USD'. Honest mistake. Still too much from my perceived value; by comparison, you can go sub to AAA studio MMO, or a streaming video sub for a silly amount more 'content' for the same or lesser price.
As far as how they are handling the 'total amount pledged is over X' stuff...my best suggestion would be to reach out to another creator on Patreon and ask how they are handling it. I've never seen the backend of Patreon nor do I deal in that area in my retail operation to know how they are going about tracking such things. You're probably right that their using some API exporting to a spreadsheet to keep running totals for each patron, along with username and email.
Beyond that, I can respect not wanting to get rid of the higher tiers for those diehard 'shut up and take my money' fans. That being said, the first step in making things more attractive is the one you've just taken, and that's ask your existing patrons / public what kinds of things they'd like to see. For starters, the donator recognition through 'name in credits' is a popular option. I would expect, at some point, you're going to want to have some kind of 'About the Team' or credits in your game to give, well, credit to all the people that worked on the game, contributed assets, etc. You obviously have coders and artists and at least one voice actress (that I know of) to credit for their work.
The sky really is the limit for what you can offer, as the best part about digital goods....they're basically free to generate. Create it once, SAVE (always save and regularly backup your work), and then just copy it 9billion times to all your subscribers. You don't have to manufacture it, there's no resources needed to make more (other than bandwidth). You're basically printing money.
For another option, lot of creators do weighted polling for 'what do you want to see next' kind of stuff. First one that comes to mind is
You must be registered to see the links
w/ Lifeplay. Does polls regularly, to line up the next 2-3 things (ie fetishes) that they work on next, and then does 2-3 updates a month, adding 6-8 scenes to each of the requested things, as well as taking commissions from high tier patrons for specific scenes they want to see added to the game. They are not trying to make a living based on thier game however, as its more of a passion project that they do and share because people appreciate it, so marketing and making more money is not something they focus on.
Another option that comes to mind, for higher tier pledges, often creators will offer limited quantity tiers, like 'the first 20 to pledge $100 can design an NPC that will be in the final game'. They give you a premise, little bit of background, you go back and forth on appearance until they're happy, and viola. You've got yourself a milfy neighbor that may not have a deep background or a quest line or dates, but maybe a dozen unique 'Talk' dialogues (I'm lookin at you Nana
)
Another idea is delayed releases of builds. Some creators will offer a 'get it right NOW/first/weekly/alpha' tier to get the build ASAP, and then a lower tier that gets access at a later date, or a monthly beta build, usually 2 weeks to a month.
You must be registered to see the links
is one such example, and a personal favorite, but like Vinfamy, they create because they enjoy it, not as a profession. It may be renpy, but that code is a work of art and feat of engineering for what they've done with it. Procedural generation using 2d images of 3d renders, billions of possible combinations of over a dozen different facial and body features. Just glorious.
Those are just a few ideas off the top of my head. Asking the folks that are in the $1 tier what they'd want to make them sub higher is an excellent way to connect with your fanbase.
If you want to see some GRADE AAA patreon tiering, take a look at
You must be registered to see the links
. This person knows how to market their game, knows what people are willing to spend, takes advantage of limited quantity tiering and tier 'sales' (never underestimate deal FOMO), and is just raking in money. Almost $4k USD in just $1 and $2 subs. They might have been able to get more from those people, another dollar or two, but they baited their hook with a tasty, discounted deal and BOOM 4grand. Their game is also available for outright purchase on Steam for $20USD + TAX/VAT/All that fun stuff.
The
You must be registered to see the links
game also markets their game and tiering quite well, as they acknowledge the value perception of their fanbase, and respond by making their tiers chocked full of 'stuff' (or at least looking like they are), which all comes at basically zero cost to them (other than time). Even their weighted voting isn't linear, but on a curve, with higher tiers getting more votes per dollar (goes from 8:1, to 6:1, 4:1, ~3:1, and tops out at ~2.5:1vote), which contributes to the perception of higher tiers being a better value.
I'm gonna end my wall of text here. Once I got started, I just kept going and going and going....You gotta ask yourself 'how do I make this look like it's value is higher than it actually is' and then find that sweet spot between margin and volume. Sometimes it's better to take a slight lower profit margin if it'll increase overall sales volume, resulting in a higher overall revenue.