SPOILER POST

To unlock Metsu Mode (Hard mode with more story):up up up up right right down at the title screen or score 40k points.

Story stuff:

First, this game has two story routes, and the ending will only show after you've completed the photo album (all 5 pictures). The condition for the routes:
A. Score above 10k and below 20k.
B. Score above 20k, ending divided to three stages:
i. Score > 20k
ii. Score > 50k
iii. Score > 100k

After obtaining each picture, a text file (memo) will appear in the game folder explaining the things they are doing at the camp, mostly about the surprise party for Ageha, the girl with the hot green socks . Each ending for route B also spawns memo that explains the background of the story, and what happens afterwards. If you've entered route B, then on the title screen if you wait long enough (or hold spacebar for some time) the background changes to a piece of story about Irisu's past.
The main character is Irisu, the so-called bunny girl. She and the other 3 (namely Uujishima, Edo, and Ageha) are all university students. The game happens at some point where they all go camping someplace.
Irisu was actually planning to kill Ageha and Edo, motive explained further below. The block crushing game you're playing happens inside Irisu's mind. How well you perform determines the route that she will take.
In the first ending (route A, of which all of you consider 'bad end'), Irisu executes the murder plan . Thus a news reporting a tragedy befelling 3 students on a camping trip, 2 bodies found while one gone missing. photo.png shows all three students being blackened out with marker, and will reset after you play the game one more time and stays that way until much later. Image of Irisu crying after the game ends probably shows that she regrets the incident.
In the second route, the first part is what you guys consider the 'happy end'. Being scared and worried since her friends still haven't come back, Ageha returned to the lodge, only to find some pieces of memo (the ones in the game folder) and a 3-shot photo with Uuji and Edo blackened out. She starts to freak out, demand explanation, suspect Irisu and badmouth her. Behind her, a bunny girl with a witch hat closes up (from outside the game window) and swings with a club....(game exits by itself)
(Restart game)... only to reveal that it was a surprise party held for Ageha's birthday! (Notice the club is actually food, maybe a bread. Her real weapon is actually the striped socks but that will be explained later.) When Irisu calls out to her, the music suddenly stops, giving some kind of suspense but it was just Irisu congratulating her.... but what's with the suspense?
A new text file appears in the game folder explaining the reason why the guys went missing earlier, and Ageha's feelings afterwards. It also reveals she wants to be alone together with Uuji, and that Uuji's been sketching some eerie cat suicide stuff (background of gameplay) which he says has no special meanings, he's just imitating some foreign cartoon which had bunnies instead of cats. She, as a cat-lover, wants him rather to draw those creepy stuff using bunnies instead of cats, and this is going to trigger something really bad later.
After this, in game menu, a story appears after pressing spacebar for long time. Irisu grew up being lonely because her family moved often so she was afraid of making one. Her only friend was a rabbit kept in schoolyard, and it wasn't popular with the kids. There was another animal kept in school, a cat which is loved by everyone, but Irisu couldn't mix in due to her asthma. One day, she found the rabbit dead only with is head, and a cat was licking it. And so she killed the cat (the outcome is actually unknown, but you can guess). Ever since, she holds grudge against cats.
Second part (>50k), gameplay ends with Irisu showing scary face. A final text file (Irisu's diary?) entitled "can't stop taking cough medicine" is unlocked and placed inside the game folder, revealing the truth behind the camping trip. Irisu found two people sitting beside her in class to be noisy, wondered what is so amusing about the chatter, and wished they were all dead. One day, her eyes met with a pretty boy who always seen alone, but gives her a warm smile. That boy was Uujishima. She had a chance to peek inside his notebook and found sketches of cats commiting suicide in various ways. Due to this, she felt that they both share the same feeling and the day their eyes met was destined. Since then, "they started to get on together" (delusion in play). Uuji is becoming more and more dear to her, she likened the distance of their seats (4 seats apart) to the fence of the rabbithouse in her elementary years, and wondered if he won't get eaten. Actually, they still haven't spoken to each other.
Lately, a girl (Ageha) is getting friendly with Uuji, and that is irritating. That cat like girl, and another stupid boy (Edo), together with Uuji, seems to be planning a trip, and Irisu is not going to let them take Uuji away. "The cough is not stopping"
After some events, she decided to kill them. For this, she came up with a plan, and started befriending the trio and even became someone who decides the matter of the trip, which is kind of a miracle since she is not used to this kind of friend stuff, but for the sake of Uuji...
An insight to what seems to be the plan for a perfect crime makes her rethink how wicked it was. She burned the notes of the plan, and instead came up with a birthday surprise plan instead. Nevertheless, she gives herself good marks for certain good points of the plan, like filling one of her socks with sands and gravel to be used as a blackjack (notice the art in the game menu).
"puts some more white powder medicine inside her mouth, the sensation coming to her nerves, and her breath is becoming easier"
The reason the plan wasn't worked out was: she didn't feel like it. Behind her eyes, there is this invisible inorganic world where she destroys something. She had always been playing this since childhood and it somehow give her relaxation. Anyways, she was glad she didn't go with it. The plan had some flaws: her target in the first place was Ageha, and there was no need to call her lover to the place of murder.
"starts to stuff more white powder down her throat. The 30th packet. The mixture of ephedrine and codeine makes her sympatethic nervous system fly~~"
This time, she isn't going to let the mood of the moment ruin her plan. And when she succeeds, she is going to sit alone with Uuji, sunset on their backs, enjoying his sketches.
Final part (>100k):
photo.png now shows Ageha's face erased/whitened out. alluding to Irisu's success in her plan's execution (Ageha's dead). So now she is going to see Uuji's sketches. Wait, earlier, Ageha asked Uuji to draw rabbit instead of cat, right? (there's another picture named u-tarou.png in game folder).

Well that's long as hell, and it isn't even the end. Next post I'll detail the story of Metsu mode.

MORE SPOILERS

So this is all for Metsu mode:

The school had a cat. It was very popular among the kids. One day, someone found a bunny in the schoolyard, so they decided to keep it in a cage. The bunny, with one ear cut off, didn't get as much attention as the cat. Not only that, but those who were seen playing with the bunny were considered "lower class". The bunny seemed to be afraid of people.
Uuji worried about the bunny, and went to see it when people weren't looking, feeling relieved every time he saw it moving about just fine. He sometimes saw the cat and the bunny play together through the fence.
One day, on his way to see his bunny, he saw a girl already there outside the animal pen. She would sometimes talk to the bunny, and feed it. Uuji found out that girl was from another class, and had cat allergy. He just looked at her from afar, heart pounding.
He never tried to speak to her, afraid of causing her to get asthma as he also played with the cat. But in truth, he just didn't have the courage.
One day, the bunny was found dead, head torn apart from its body. They said a dog did it. The body was found hidden somewhere apart from where the head was found.
Ever since, the girl could no longer be found at school. And neither could the cat.
Uuji realized he has been drawing dying cats for some time. He wondered why it was cats...
The day before, a girl in a group behind where he sits, Ageha, was chatting with her friends enjoyably. She said "If I were an animal, I'd probably be a cat" "Yesterday's animal fortune said I was cat!".
Cat? Cat, Cat, Cat... Uuji was thinking about that when he was busy moving his hands.
The group behind him was always talking bad about him. He didn't care, for he had his suicide cat sketching to fill his time with. But one day Edogawa started complaining to the group, and they had a quarrel. Uuji didn't care, and the point of the quarrel never got to his memory.
It seemed that Edogawa had a crush on Ageha. Ageha didn't seem to realize it, though.
Ah, there was this pale girl who was always alone. Sometimes her eyes met with Uuji's, and he would just smile back. It seemed the girl's name was Irisu Kyouko, and she would always be seen alone.
Uuji saw that Irisu took a peek at his notebook. "What a wonderful girl," he thought, and waited for her to go back to her seat before entering the class. She sat as if she didn't do anything suspicious.
"Ah, Irisu Kyouko. What words can describe her? Looking at her gives me joy. I feel like I want to be killed by her," he thought.
Kyouko seemed to be sitting closer to him lately.
"Would be better if she came even closer..."
There had been traces of someone touching his notebook, especially in the pages with the cats. "Would be better if she looked at it more..."
Drawing the cats had been his daily chore. Since he was using notebooks especially for drawing them, he already had ten notebooks filled with the drawings.
He had never once spoken to the girl. The notebook was sufficient as their means of communication.
It seemed that somewhere overseas, there was a similar picture book like his, but it has rabbits instead.
One day, he found Ageha, who wasn't feeling well, in the corridor. She seemed like an anemic cat. He brought her to somewhere where she could rest, and that, he thought, was the root of the mistake.
Some days afterwards, Edogawa called out to him, with Ageha smiling beside him. He wondered why. Nevertheless the three of them began talking to each other. He didn't understand it, but they started to be together more often. Uuji couldn't find the time to draw cats.
Ageha had started becoming closer to Uuji. Before he knew it, she was calling him by his first name already. Since the appearance of the two, the chances of showing the notebook to Kyouko had greatly reduced. Uuji was troubled.
Ageha looked at his notebook without permission. Uuji didn't like it. Ageha seemed to be having fun. Uuji tried to find a good reply to her that would make her think he was crazy, so that she would keep away from him, thus giving him more chances to be with Kyouko. But he could only say "the pictures have no special meanings."
For some reason, the three decided to go for a trip. Why? He didn't get it. He didn't understand the purpose. He'd rather be sleeping at home. Ageha started becoming more intimate with him, and Edogawa was unnecessarily apprehensive.
Summer was coming. People started to wonder why Uuji was still wearing long sleeves. His wrist had something that couldn't be covered with a watch. Never mind. He just decided to go along with the two and make them think he was having a great time.
Uuji wanted to be connected with Irisu again, so he took a peek at her notebook. He found it interesting: written in it were details about a certain "plan". Also, it seemed that the two of them were considered to have steady relations in her writing; that made him happy. The fact that she had strong love for bunnies and hatred against cats left a deep impression inside him. He was very happy with the notebook; it kind of extinguished all those grudges against Edogawa and Ageha.
The "Plan" went like this: the four of them would go to the trip. And as they had fun, Irisu would kill the other two.
One day, in the library, Irisu spoke to the three. She seemed nervous, but got good reception. Uuji's heart began racing, not because it was the first time he heard Irisu's voice, but because he remembered this development from her notebook. The "plan" was to be executed on Ageha's birthday.
If the plan went well, Uuji would get to be together alone with Irisu.
But wait, if the other two do get killed, and Irisu disappears without trace, what would he answer to the police? No, it can't go like this. Hmm, couldn't he have Irisu change the target to him instead? I get to be killed by Irisu, that'd be the best happy ending for him! Even better if she were to die together with him, but that was too much to ask for.
Irisu's plan would proceed well. Bunny-eared Irisu was wonderful!
Somehow he found himself alone with Ageha. She complained about the drawings. He replied "I'm just imitating a certain foreign work." And she said "Then draw it as it originally was!"
Drew lots of dying bunnies.
Drew lots and lots of dying bunnies. Ageha's idea was very splendid! Considering Irisu's love for bunnies, wouldn't this be the correct solution?
If he drew bunnies.
If Irisu who's in the middle of her "plan" saw it.
What would she do to Uuji? He got excited just thinking of it.
He drew more and more bunnies as the day for the trip drew closer. The night before the trip, he remembered a certain event from the past.

Continued in next post.

On a rainy day, the boy cut off the rabbit's head using a saw. Splatter. His hands got smeared with blood, fat, and unknown fluids.
The head was severed from the body, placed on the floor. The silent rabbit head seemed to be staring at him.
Getting out of the cage, poured on by rain, the boy brought the body to a certain corner of the schoolyard and hid it in the bushes. He went to clean his hands and the saw, making sure no traces were left.
He woke up. It had been such a long time since he saw that dream.
Uuji saw a dream where a pair of red eyes was saying something. It didn't get off his mind.
The day for the trip came. Uuji confirmed his current feelings. He believed Ageha and Edo were stupid. Ageha for being nice to him. Edo for leading her to him. Now if they were to know the reason why he kept concealing his wrist, how would they react? Would they still be in contact with him? Yes, they would. Stupid fellows.
Hmm, now that he considered it again, it wasn't good to get the two involved in his plan. What was for sure was that Ageha shouldn't have had feelings for him in the first place. No matter how you looked at it, Ageha and Edo were better off together. If things worked out, the four of them might come out fine and dandy.
Now
If.
If Irisu's plan didn't work out, Uuji wanted to challenge something: getting the relationship of the four in the right place. That is, to change the small world they're in. Then Uuji could get rid of his past, and look for another ending.
Off they went for the trip.
Uuji is wondering if this the ending that he wanted, and whether he's satisfied with it.
Early morning, he went to see the rabbit's condition, choosing the time carefully so he wouldn't bother the girl. As he peeked through the cage, he saw that it was dead. As if sleeping. He wondered if it got sick of living. And he wondered what was born through the death of the rabbit, and also of the future. The animal pen now had nothing. The death of the rabbit would not be cared for by anyone. And the girl would become alone again.
Such a future was unacceptable.
To change it, the boy ran to get the key to the cage. It was suddenly raining heavily. Exasperatingly, he continued running, trying all he could to change the future. So that the soon to be forgotten existence of the rabbit would remain in somebody. At least so someone would think how pitiable it was. At least, let the rabbit become a topic of talk. In any form. So that the girl, who was looking after the rabbit, would get to talk with everyone. Thus, surely she'd get to blend into them.
Was he correct in doing so?
Well, the rabbit did get some attention. "Scary..." "Gotta be careful from now on" Only those words are talked about regarding it. The cat which went missing was the center of everyone's discussion.
A couple of days later, the cat came back. Everyone was happy. No one remembered the rabbit anymore.
What happened to the girl? Unknown. After the incident, that girl was no longer seen.
The boy wondered, whether he did the right thing. He couldn't change the future.
At the very least, he would remember about the rabbit with the bruises.

Done. Goddamn that's a long story.

So yeah, play the game, have fun, and please don't post pictures of spoilers.

Oh, and I should probably include that there is another expansion in the works called Irisu Syndrome: Kai (or Irisu Syndrome: Solution). Pic is the teaser.

HEY LOOK AN ENGLISH TRANSLATION PATCH!
http://www.mediafire.com/?nlujzb91wjl0bu7
Too bad it won't translate any of the text files you might have already earned.

THE IMAGE IS SPOILED FOR A REASON. PLAY THE GAME FIRST.