So I am developing this Super Mario Bros clone, which looks exactly like Super Mario Bros for NES. I didn't change any graphics, they are ripped straight from the game using the emulator. I'm trying to copy exact behavior of the game, from the physics, to the maps. At this stage of development it looks like this (I took the screenshot from the my device):

And I am thinking of publishing it to the Google Play. This may be a stupid question, but I know I could get into some trouble, couldn't I?

I read on other sites that Nintendo seems to be pretty liberal in their treatment of derivative games. So could I get into trouble by publishing it to Google Play?

If so, then what could I do to minimize the risk of me getting into trouble? Maybe if change the color of mario, or change position of few pixels, it won't be considered mario anymore? Because I read somewhere that if you edit the copyrighted content just by a little bit (for example, changing the pitch of music) you can use it anywhere you want, is it true?

Thanks in advance.

they are ripped straight from the game

Then they're Nintendo's property.

I read somewhere that if you edit the copyrighted content just by a little bit (for example, changing the pitch of music) you can use it anywhere you want, is it true?

No, that's a myth. It's known as the "10% rule" ("if you change it by 10%, it's no longer copyrighted"), but it doesn't actually exist. If you modify them, it's a "derivative work", which is jointly owned by you and Nintendo. You still need their permission, as they still own it.

If so, then what could I do to minimize the risk of me getting into trouble?

Publish it under a fake name so they can't find you

Worst case: They sue you right away.
Likely case: They eventually notice you and threaten to sue you if you don't take it down. You take it down to avoid being sued.
Lucky case: They never notice you and you get away with it.

If you want to be legit, then you'll have to remake all the artwork yourself from scratch.

Well technically you can because there are quite a number of Super Mario clones already on Google Play. In the best case scenario, Nintendo will tell Google to remove all of the clones. The next best thing is that Nintendo tells Google to take down the clones and sends you a letter telling you never to do that again. Worst case -- and high likelihood-- Nintendo sues you for copyright infringement.

This all begs the question of why you (or anyone) would want to do this. The world already has Super Mario Bros. You should make something new that the world hasn't seen yet and add something positive to the sum of human culture, instead of pouring in another "me too, me too" copy of something else.

This all begs the question of why you (or anyone) would want to do this. The world already has Super Mario Bros. You should make something new that the world hasn't seen yet and add something positive to the sum of human culture, instead of pouring in another "me too, me too" copy of something else.

Why? Because I wanted to make a game that is already out, so I wouldn't have to design the sounds, graphics, levels, gameplay mechanincs and so on. This way I could learn how games are made in greater detail without all the hassle of thinking brand new game idea. And I know this might be hard to comprehend, but game development is my hobby, and I find it very enjoyable. That probably would be the biggest reason I do game development.

If you want to be legit, then you'll have to remake all the artwork yourself from scratch.

Thanks Hodgman, but would it be sufficient enough to just remake all the artwork? What if did new artwork and I kept the exact same level design?

Why? Because I wanted to make a game that is already out, so I wouldn't have to design the sounds, graphics, levels, gameplay mechanincs and so on. This way I could learn how games are made in greater detail without all the hassle of thinking brand new game idea. And I know this might be hard to comprehend, but game development is my hobby, and I find it very enjoyable. That probably would be the biggest reason I do game development.

To do it to learn is admirable. To turn around and try to make a profit off the hard work of others is contemptible. If you enjoy game development so much, then do game development. Game development includes asset creation. It also includes creativity. There's nothing creative about copying another game point for point. That's not game development, that's just game copying.

If you want to be legit, then you'll have to remake all the artwork yourself from scratch.

Hodgeman is spot on.

rule of thumb-- if you didn't create everything in your game yourself, pay someone to create it, or license it, you are almost certainly infringing on copyright and/or trademark

Note, though, that even if you remake the artwork from scratch, if it's mario, then it's still copyright infringement, even if you created all the art by yourself.

To paraphrase your 6th grade English teacher, you can publish your Mario clone to Google Play, but you may not.

To do it to learn is admirable. To turn around and try to make a profit off the hard work of others is contemptible. If you enjoy game development so much, then do game development. Game development includes asset creation. It also includes creativity. There's nothing creative about copying another game point for point. That's not game development, that's just game copying.

Who said I was to make money out of it? I would make it free, and maybe even open-source. It wouldn't feel right to make money out of other peoples' hard work. So what if I don't have much creativity. I'm a programmer first, gamer second. I don't think my second EVER game should be anything mind blowing, or very original. So I thought why couldn't I make a mario clone. At first, I really didn't want to make clone of ANY game, I just thought that I wouldn't get far with that. But after some time I realized: WHO CARES? As long as I'm having fun, it's great. And for some reason I'm having much more fun remaking this classic game, than creating my own crappy one.

Thank you for clarifying, bschmidt1962. I will keep this in mind.