"Attempt" means that I tried to figure out how to get all the endings by running Japanese capture guides through translation engines and making sense of the resulting gibberish, and hacking the save files. It also means that I didn't quite succeed. The scenes that show the unicorn in the forest, Liam as the new teacher at school and what I assume is Lugh's love ending, still elude me. But I've succeeded in reconciling the two sides, which is the supposed best ending of the game.
Untypically, this game's "gallery" only stores events, not endings. Therefore, the player can't see how many endings are available from checking the number of empty rectangles in the gallery. The ending scenes are briefly shown and then fade to make way for the credits, and the only way to get a second look at them is to either buy the art book or save the game the day before the ending happens. So I'll explain something about game files: the gallery settings are stored in a binary file called "dataglobal". Changing certain bytes to "01" in this file makes all events visible, both between Liam and the game characters, and between the game characters themselves. The forty save slots are binary files called "data[nn]" so the files for the save slots 1 to 10 would be "data00" to "data09". These files can be opened in a hex editor and hacked to alter the numbers of each herb in Liam's inventory, the day number, the time of day and the level of sympathy between the eight visitors and Liam, or between one visitor and another. And, it turns out, the latter is what gets potion endings, instead of love endings. So, to see either kind of ending again, save the game before it happens, and copy the save file to a name like "glaumerie" or "tim" to indicate what ending it is. To replay the end, choose an unused save slot, copy the saved file back to the save- slot file (for save slot 28 this would be "data27") and load from that save slot. This can be done while the game is running.
By hacking the save files, I discovered the meaning of the two golden buttons in the save screen. This screen, opened by clicking on the desk, shows many parameters stored in the save files, primarily Liam's inventory and popularity with each character. The angels and demons are represented by two columns of four buttons each, the top two of which are golden. But that's only the focus colour. I can shift the focus to the lower buttons. If I choose the buttons of two characters (always one angel and one demon) that get on well, the round lid of the bottle changes colour; the more they like each other, the redder it becomes. If they've grown to hate each other, which is harder to arrange, it goes light blue. So it has the same function as the eight appreciation bars.
To recap: there are love endings (Liam strikes up a relationship with one of the characters, which prematurely ends the game) and potion endings, where the potion is finished and turns out to be one of a number of kinds/colours. The love endings are obtained by using only the target's herb, supplemented with the corresponding fairy herb if in short supply, giving the character the right responses (and making sure a character of the opposite side doesn't burst in to ruin the conversation), also giving the right responses during outings (especially the third outing, so Liam gets a gem which is like a herb, only much more potent) and, finally, not snubbing the target when he pops the question in the fifth event. (The sixth event - the night-time visit - is not all that important.)
The main mechanism behind love endings is to do what it takes to lengthen the character's appreciation bar in the save screen: use the character's herb (or Liam's local equivalent, for a weaker effect) and make the character happy with the right replies. The main mechanism behind potion endings is the same, only this time it's two visitors that are hitched, and Liam can't directly influence the conversation. A conversation between an angel and a demon ends in two ways: they argue and leave in anger, the second one not getting time to hand over a herb (this decreases the relationship between them, as well as preventing the relationship with Liam from improving) or enough of either's herb has been mixed to make them feel at ease with each other, in which case they both hand in their herb and nip off to the woods together, not hanging around to talk to Liam (which means no improvement in their relationship to him, and no extra herb, and probably improves their relationship each other). So the thing to do is to mix the herbs of the two characters to be reconciled, and make sure they don't meet before selecting their two buttons in the save screen makes the lid of the vial turn red.
The more the two opposite sides are reconciled with each other by setting them up as couples, the more successful the potion. From barely understood conversations with Liam's teacher, I get the idea that the best combinations are one side's branch with another side's leaf and one side's flower with another side's berry, although any angel can be fixed up with any demon. The total amount of "harmony" between the opposite sides determines how well the potion turns out. As such, it doesn't really matter who likes who, how romantically involved they are or even whether they're monogamous. What matters is that Liam prevents fights and arranges visits so that he gets an equal number of herbs from all visitors. Although on his first day of mixing he only has herbs from the fairy grove (and what herbs he chooses will have an effect on which visitors come first) ideally he shouldn't need any fairy grove herbs at all for the rest of the game. It's a good idea to visit school rather than the fairy grove on "picking" day anyway, for a reason which will be explained in the example below.
Let's say I want to match Nadhew (the biggest badboy) with Tim (the whiniest goody-two-shoes). To get a well-mixed potion I'll have to match the others as well, but I'm picking out these two for simplicity's sake and because they're a funny combination. On the first day, I'll mix three times fairy branch with fairy acorn. This should bring them to the top of the visiting list. Now I want these two to give me plenty of their herb for mixing, but at the same time they shouldn't meet just yet. So I'll give Nadhew replies that don't anger him but won't keep him sitting around for a second turn, either. The pink/purple replies produce the strongest reaction, but it's also possible to choose buttons that represent the other members on his side, and using these will usually not cause a change in expression. Assuming Tim is the second one, I can butter him up as much as I like for that second bit of herb. Because I don't want later visitors to interfere, I'll have to be cold to all other characters to move them to later visitor slots, although I'll still be putting their herbs in the mix to avoid having to resort to fairy herbs. After these two visitors have left, I'll put water on the herbs and add them to the mix while they're still strong (dark blue means strong, greenish-blue means the effect has faded). The two may change places, Tim becoming first visitor and needing to be gotten rid of before the second arrives, or, if I have enough herbs, I might both mix and add first thing in the morning, which has the strongest effect but uses up the first visitor slot and automatically cuts out my favourite, causing him to fall out of favour as the less popular guests catch up with him. Once enough Nadhew-branch and Tim-berry have been mixed together, if either is still inside when the other arrives, they'll greet each other, excuse themselves, and leave together. If Liam goes to the fairy grove rather than to school on herb-picking day, he risks accidentally spotting them having a talk together in the forest. This decreases both their red bars to zero, meaning they'll like him least and will from then on turn up latest in the day, if at all, which is a nuisance when trying to capture events. But if I want to set up the next couple, at least the first is safely out of the way.
As said, angels and demons don't have to be set up as couples for a best ending, although having them get along makes herb-collecting easier. The important thing is to always put one angel herb and one demon herb in the beaker. Fairy herbs can be used when the other herbs are in short supply, but combining two angel herbs or two demon herbs is a waste. Any visitor can be set up with all visitors of the opposite side, so theoretically it's possible to get gems from more than one character and mix them together or score forest events for one demon with all four angels, but that takes a fair bit of manipulation, and planning such outcomes is a lot harder than playing the game as a straightforward dating sim. The exception is the combination Sittra/Tim; if these two are set up together, they will both latch onto Liam. I don't know what effect all this couple-creating has on the game's best ending, but suspect that it's connected with these extra ending scenes that I'm not getting.
That said, on to the potion endings. I've managed to get the following potions:
Mera or Lugh-Cifer: total discord. Both are the same oily red potion, but if Liam is more popular with the angels, his favourite demon shows up and kills him ("Mera"). If he's more popular with the demons, he's taken to Annwn (possibly after being killed, since Annwn is, among other things, an afterworld) leading to Cifer's love ending ("Lugh-Cifer"). "Mera" is an Old-English word for demon.
(There is a sparkly purple potion between these two and the next that I haven't managed to capture yet, and so can't name.)
Pishogue: no agreement. A dull grey-blue potion. Liam's favourite angel shows up to tell him that, alas, he hasn't succeeded, and he's very sad. "Pishogue" is an Irish word for an evil spell, something like "bad mojo".
Glaumerie: some agreement. A sparkly lilac potion. Liam's favourite angel turns up to say that, alas, he hasn't succeeded in mixing the proper potion. He goes outside and meets this angel in the company of his favourite demon, and they tell him not to worry, they'll figure it out from here. The demon says a last fond farewell (which is particularly funny in the case of Claydle, who would rather lose his arms and legs than admit he cares about anyone: "Hey, kid. Goodbye.") and Liam consoles himself with the fact that his efforts weren't totally wasted. "Glaumerie" is an old word for elf magic, or for "faerie", which in itself means elf magic: bewitching people's senses so that they think leaves are gold coins, and the like. The modern word "glamour" was derived from it.
Naoverie: mission accomplished. A sparkly bluish-white potion. Liam's favourite angel comes to fetch him for a visit to Flaithis, where he is surprised by a voice behind him and sees all demon visitors in a row. Next, Cifer shows up and shakes hands with Lugh, who does a little reconciliation speech. Finally, Liam sits in the victory chair with Lugh and Cifer bending over him while the angels treat their guests to fruit and Claydle looks at the apple he's just been offered with a quizzed expression. (Which is ironic in two ways: from the Christian viewpoint, the apple is the fruit of original sin, so angels handing out apples to supposedly sinful creatures is rather patronizing. From the pagan Celtic viewpoint, apples are fairy fruit, the apple tree being the entrance to the Otherworld, which in Wales was called Annwn. I doubt the gamemakers were aware of either.) "Naoverie" - the "o" is written but not pronounced - is not an existing word. It's pronounced as "naverie" which is French for fleet or armada. As such, it would have unpleasant military connotations. But it may simply be a fantasy word.
It's possible to get the best ending just by setting up one or two couples;
their mutual affection will cancel out all other bad feelings between both
sides. The extra ending bits - Liam becomes a teacher or is swept up by Lugh -
are probably added when all enmity is gone, for which every character's herb is
mixed more or less equally with every other character's herb.