It didn’t feel out of character of the Vader we see in Revenge of the Sith who cut down younglings. It doesn’t fit Vader in the original film though.
I find it to be more equivalent to the cutting down of the Separatist leaders on Mustafar as we never actually see him cut down the younglings. In the former sense it does work.
My problem with it is more to do with that he’s supposed to be more machine than man. His movements are very fluid for someone who has each limb as mechanical. He’s much more restricted in his fights with Obi-Wan and Luke versus what is showed in the hallway. I also don’t feel it fits his character as by the time of A New Hope he’s overcompensating with intimidation and fear through force. Pun not intended. Haha. He’s grown into his role as an enforcer through fear compared to where he was when he pledged himself to the Sith. At that point he was doing what he thought was right to save the ones he loved. He would’ve done anything at that point but that changed when he believed he lost everything. He realised he couldn’t go back to what he was before and continued his commitment to the Dark Side.