This episode had an intriguing premise. In fact, a small clip of this episode from the trailer got me excited for the entire show. But after watching it, i was quite disappointed. It definitely is enjoyable and it isn't the worst episode, but it could have been so much better.
First of all, killmonger's character has been portrayed really well. It was interesting to watch how his menacing side unfolds as the episode progresses. Also, the episode has no unnecessary humor which has been a recurring problem in the previous episodes. The pacing was quite decent too.
However, the episode fails to generate the necessary thrills that the story demands. It is very predictable, you can litterally picture how it is going to end too. The other supporting characters as well as tony's, feel extremely and quite shockingly underutilized. Hence, the episode feels bland and forgettable despite having some cool moments.
To sum up, the episode falls prey to poor execution despite having a great premise. Killmonger's character has been given justice and it was really enjoyable to watch that but that's pretty much it. The rest of it falls flat and fails to be a compelling watch.
P. S - This episode (like a few others) ends on a cliffhanger which doesn't really makes sense for a "What if...?" episode unless there's continuation of the episode in the future.