I don't know anything about Harry Potter.
Before a couple days ago, I'd heard a lot about Space Engineers but didnt know shit about what you actually did or what it was, but I was curious so I looked at a couple of videos. Now I'm convinced that I need it because it looks so fucking cool, but I keep hearing shit about how the devs barely ever add anything or how it performs badly or how it's wicked buggy. This is less of a "WTF" moment and more of a "WTF DO I DO" moment.
I play with it modded to shit and back and I've never encountered a bug or glitch that I noticed as such, so I seriously doubt that there's much of an issue in vanilla.
Unless you're talking about multiplayer, not enough people on for me to have any real experience with that.
Just, uh. Fair warning. It's like someone took the most boring parts of all the Elite/Freelancer-esque games and made it into a game, then added construction. It can get really engaging and immersive, but at the end of the day you're spending hours staring at space rocks and welding/grinding bits of hull together. So that you can have a bigger ship with which to poke space rocks and a better base to park it at. The opening bits of a survival save are tense and fun (if you didn't pick any of the pussy-mode starts that give you more than a crap ship/wreck and a few minutes of fuel and air), but that's about it for pressure.
Combat's a joke, to the point that all important AI-controlled ships are booby-trapped to explode if you use their thrusters at all, because it's taken for granted that anyone even mildly competent can successfully board even the most heavily armed ones.