I liked Skyline (2010). It had a lot of action, interesting style (blue/red light, which I interpreted as something the characters don't actually see), and despite not being particularly smart like Arrival (2016) it was engaging until the ending I found very satisfying. I'm honestly surprised about most reviewers who seem to have expected a different genre altogether and were disappointed the characters aren't as deep as they think they are ;)
Beyond Skyline is simply more of the same, and I mean it. After it neatly blends with the original, it escalates the action, offers more of the same style (might be a tad too much, though), still not very intelligent yet avoids being unforgivably silly, and even delivers an ending I couldn't be happier about. It tries to avoid the mistakes of the first movie, like characterisation or dialogue, but it's debatable whether it worked. Definitely supplements the original and makes the series better than the sum of its parts.
In short, it's a lot like Independence Day (1996), much better than the sequel (2016) and provides a nice alternative to it.
