Koroshiya 1 The Animation: Episode 0

Both "Gantz" and "Ichi the Killer" are shocking, disturbing, dark exercises in ultraviolence. Both series will show you disturbing images you probally don't ever want to see, but like a train wreck, you can't look away. Also both surprisingly have a large amount of dark humor. Half the time your watching these anime series you will be laughing, and the other half you will be repulsed. They are both full of gore, sex scenes, screwed up scenes, and show more blood then most other anime series, in a shorter time then though possible. The music in both series sound very much alike. From background music to the songs used, they all sound very much alike. Both series music seems to be inspired by rap, and their odd beats seem to match the dark ultraviolence of each show. Listening to the opening themes of both series back to back (which sound a like), might want to make you do some killings of your own... Both series also have character designs that look the same. They seem to both have that weird "ugly" seinen style designs, that work for each show. The characters in both are very well detailed, and look almost ugly (the intent sometimes) and realistic. The characters in each series are also a little alike, so it's fitting they are drawn the same way. If you liked the dark comedy/ultraviolent horror that was "Gantz", give "Ichi the Killer: Episode 0" a try (or vice versa)... read more 

The main similarity between these two anime is the profession of the their main characters, as they are both assassins. Also, both anime contain a lot of violence and nudity. The main difference is that Ichi the Killer focuses more on the characters' psyche. 

[18+] both follow a guy who is happy seeing other in pain except one is psychopatic killer and the other is H sadist. 

Both anime consist of psychotic male main characters that commit immoral acts on people. However, Koroshiya 1 The Animation: Episode 0 is much more brutal and gorier.  

Both are anime that portrait the bullying and the repercussion it has on the person. Both are older anime and have trippy animation as well as the narration. Both are dementia genre and as dementia anime tend to do, they have interesting plot twists and overall mindfuck. Both have violence as well as nudity. 

ichi the killer is a more violent and sickening orientated mob anime than don and revolves more around 1 killer than the actual gang , don first give's attention to 2 charachters, but both have the mobster like feel to it and gangfights 

Gore & violence, no remorse, killing in one shot. 

Not for kids: both have that´heavy psychological´mindfucks that deflects of the main charachter about pretty everything he/she goes through, especially for an oldskool masterpiece like perfect blue wich goes more on the ´thriller´side, Ichi the killer is more violent on a gore side wich goes out of control, i like them both!!! 

NOT EVEN FOR 18 + both involes crime syndicates at war and Sick assasins to do the dirty job, and both have that ´ordinary person that has the killing skill´ type. cruel and violent!!! 

Both are anime about a crybaby with psychological problems that has a mental breakdown and explore hidden power. Both anime are dementia genre. Both have interesting, original plot and plot-twist. Both have also nicely done animation (while End of Evangelion has high quality animation in general, Koroshiya 1 has lower quality one, but it fits the anime perfectly). Both anime have gory and disturbing parts. If you liked one, you may like the other one.