So here's the plot:

Two siblings find out about a top secret portal into other realities. Two years later, they get forced into said portal and have to find a way to get back to their home. The only problem is, they need the portal where they're from to exist but their universe is destroyed because of reasons I have yet to figure out yet. Yeah, I'm in the early stages of writing this. I'm only on like, the first chapter.

Anyway, please pick the one that's the catchiest, makes sense for the plot, and is the most eye-catching or that intrigues you the most to read it. If you have any ideas for other titles or what I could possibly change about the titles to make them better put me here please! I'd love the feedback!

The other two are too long to be catchy, IMO.

This one definitely caught me eye first. I guess if you're in the early stages, you still have time to make any of these titles make perfect sense. Although from what you've told us, the other two potential titles make it sound like the characters want to explore the alternate realities, whereas the plot you've got so far makes it seem like they're not trying to escape from their own reality or choosing to explore other dimensions; it sounds like it was an accident and they just want to get back to their own life.

Maybe the way they get forced into the portal could be caused by something that can be described as a "glitch" (and maybe that's even what you already have in mind!). I like that this title is short and memorable. Only slight issue is that a story called "Glitch" link, but I'm sure we can think of other book titles that have been used more than once!

Could even call it "The Glitch" I guess, to get past that problem. Either way, I do like this one. :)

^^^Thanks for the feedback.

I didn't explain what the term 'glitch' means in this story. It's pretty much just a glimpse into another realities timeline or two timelines overlapping somehow, which is partially why I'm not using it at the moment. The characters are traveling in between various universes (a.ka 'leaping') . Also, you're right about stories with the title 'Glitch'. There are a lot of those on Wattpad, which is where I'm putting this on.
But the reason they end up in other realities in the first place is either gonna be an accident, like you suggested, or they get forced to go by their father because the world is ending. I'm still deciding.