The Dev puts more work into encrypting/obfuscating the files than they do actually creating the game... That's why it needs a ton of RAM to run well, as the game is decrypting the files as you play. Older versions that have been decrypted play much smoother on older computers.
That has more to do with over-aggressive caching... Almost everything is cached on startup. As you may expect, the cache itself contains unencrypted content. The problem however is the sheer amount of files being loaded and permanently kept in memory... You can get around that problem by editing plugins.js and either disable it or make it less aggressive.
As far as I can tell, aggressive caching used as some half-assed workaround for various scenes/events not working properly (due to content not being loaded fast enough and not waiting for content to load completely, resulting in fatal script errors).
To be frank, the encryption and obfuscation is half-assed too. Initialization vector containing consecutive zeroes (exposing the encryption key, making it much easier to crack). Acient XOR techniques (which I haven't seen since the Atari/Commodore era) and mostly using 3rd-party scripts (the lz-string plugin used is roughly 4 years old but it's hard to say exactly since the copyright preamble was stripped off and only having the minified version). I'm pretty sure they used some off-the-shelf obfuscation tool too, sure looks that way.