You simply didn’t get the ending. You have to watch it at least two times to get it. I made a comment (about what the op missed in his post) regarding the ending which might interest you.

My favorite manga and Urasawa work is 20th Century Boys. It's so damn good.

Like I mentioned on another comment. The license for the anime expired years ago and it was pulled from everywhere as the company with ownership never bothered to renew it. For the foreseeable future the only way to watch it in the US is ilegally. 

Only way to watch it now is pirated sadly. I don’t remember the exact year, but the anime’s license expired and no one has bothered to renew it. There’s literally no legal way to view it and I believe the box sets were never even finished, at least not in US. I have the only box set of the animw that was releases in…

I’ve done this several times in the past and I will do it again now. You’re missing the real ending here. It’s not when Tenma and Johan face off in Ruhenheim. It’s not the last episode for a reason. Something that I noticed on my second watch through. Episode 74 poses the ultimate question “Who was the real monster?”…

Alternate like in your example.

Props for having Gesicht as your profile pic. I love Naoki Urasawa’s works, haven’t funished Pluto though. Only Monster and 20CB.