Nice game!
Sadly, this game broke for me twice once I got to the doors. I assume this is more of an itch problem than yours, but I wasn't able to tab back into the games after inputting the password. So hopefully there wasn't a ton more left after those.
When the "multiple applications" theme was announced, many people were afraid of the scope of having to make windows of a game, since that can be a complicated task to manage within a single week. I didn't think about how you could build 2 different versions of a game and have them play out in different tabs though!
Although, with the games being separated into two actual different games, it can be hard to design things that are more than just "this screen has a invisible platform that is only visible on the other", this is where I think having two "games" be ran on a single game is better, since you can have more intricate and complicated interactions between the two.
I was trying to think of ways to have more interactions between the two games without making them into one, and it definitely is very hard. I can only think of more things like the door, where other information is revealed that is different than an invisible platform or spike. You could also have some more complicated interactions with the invisibility. Like maybe have some laser that keeps turning on and off because an invisible enemy is hitting a switch somewhere. So you can time when the laser is going to go off with the other tab.
The worlds themselves also feel very similar, which is part of the point, but I think that having them be a little more unique might make them more memorable. Maybe having some sections where a single world has an entire path that one side doesn't would help in making the sides feel different.
The actual platforming controlled well. But, I think there are some minor design flaws in the level. It opens with a blind fall, which is normally a big no no in platform games. It was also hard to tell where I was going, and felt like I was playing some sort of sonic level with many branching paths. And I think that more distinct and linear experiences would be better for a game like this.
Having some little decorative bits next to the spikes and such were very nice, since they remove a bit of the frustration of navigating invisible objects with some subtle indicators.
I think that there could be some more visual distinction between the two games. When I first started I felt like it was the same game since nothing was different on the very first screen.
All of the art was nicely made! Very simple and clean, all fit together nicely.
The music was also good, but had the problem of playing out of both games. Good thing you added a mute option :)
I'm interested to see how the two different games get rated as well, hopefully they all get rated the same and end up near each other.
Good work!