When you click on the plant in Rabbit's hideout game says "Every professional needs a plant". People who watched "Léon: The Professional" will get it. But the most interesting is call to the "Long Boris" (maybe his name stands for something?). When you choose the number 555-7243 it answers with music from Episode 1, and after some time he send me a message with scrambled hidden information. I don’t write the message here, because it’s some kind of spoiler.
This game is full of interesting red herrings. First of all the message Mad Hatter leaves you on the glass is determined by your behavior - which reply options you've chosen. The word that appears on the screen when you look out the hole is "OYSTERCLOUD" - you can look it up on the computer. The text from the newspaper, beginning with "Over the past 6 years 42 people on the Heartland Council [...] have gone missing or died" suggest that number of victims isn't a coincidence. 42 is meaning of life. "Heartland" supports motive of hearts which can be found several times in the series (for instance - Mad Hatter have in head card of hearts). The number on the exit doors is 84 which equals 2x42 - I'm sure it's not a coincidence. That's all I've spotted, if there are more you can probably find them in Alice is Dead wiki.
I'm pretty proud of myself :P The last level terrified me at first, but today I was bored on one of my lectures, so I tried to mathematically calculate how to place the tiles. After counting all the tiles etc. I managed to calculate quantity and sizes of the spaces without tiles. Surprisingly it worked because I beat the final level in about 3 minutes :) This method is too complicated therefore useless in most of the levels, but the last level (many tiles, simple board) is perfect for it. Overall it took me about 25 minutes so it's possibly faster than I'd solve it with only shuffling the tiles.
I have to say that "Poetic End" isn't Das654's observation. On the last scene, after beating your "opposite side" you can find some anagrams of Depict One appearing one after another. Poetic End is the last one.
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 "Hexiom"){kind=icon}
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Its a bug soon updating. You will get the badge.