This was, by far, the most interesting "What if..?" episode. It gets to the point right from the beginning and keeps you engaged all the way to the end. The pacing is perfect! It's fast-paced and yet it did not feel rushed at all! It's quite suspenseful and adheres to the classic murder-mystery genre involving the OG avengers.
Unlike the first 2 episodes, the humour in this one was actually improved. The comic bits are really funny and it is quite evident that these bits have been basically used to cut the tension and dail down the dark tone of the episode. Hence, it sort of felt like a dark-comedy.
The only issue i found with this episode is that it becomes slightly predictable after a point. However, there are other minor plot twists that pop up after the "big reveal", which kind of negate the overall predictability of the episode.
This was a risky episode with so many things that could have gone wrong but it deviated from that landmine and delivered a total blast! Brilliantly executed and something different from MCU!