@protomation mmmh, I believe it wouldn't be bad for it to be able to attack, as it doesn't really make sense it woulnd't (assuming it's a natural, if prodigious, predator) afterall it spotted the girl and is clearly stalking her.
Also it would probably give the demo some more needed spice, considering you have removed the ghost king, and the octopus being a natural threat would fit the bill perfectly, without cheapening the impact of the mummies.
I also suggest the addition of some more natural enemies with varying degrees of power; assuming this is Central America I'd suggest: coral snakes and lanceheads (could perhaps introduce a venomous status effect in the game and they should behave pretty much like the spiders do), american crocodiles and piranhas (could be a more recurring threat in water levels, specially if you introduce the ability to swim at a later point), giant constrictors (could serve as an aggressive counterpart of the defensive venomous serpents mentioned earlier, though there's the issue anacondas are only found in South America) and cougars/jaguars.
I do wonder if a giant constrictor would be a more fitting choice as a water boss than an octopus considering the setting, but I would not overstep my boundaries for feedback, there might be a lore reason for why you choose a tentacled creature and not something more likely to be found in a place like that, maybe it's not a giant octopus at all but something far worse.
CrocEye
Can you be attacked by the creature those tentacles belong to?
protomation
Not right now but later in the game there will be a boss fight with that creature.