Petri Puhro is an indie game developer. He gained an internet following by developing a series of small games over the course of a year - inspired largely by the experimental games project.

He posts these games on his blog -

Recently he started work on a deluxe version to one of his most popular experiments, Crayon Physics, and he was kind enough to answer a few of my slightly rubbish questions that I sent his way.

Hi Petri - let’s start with the basics - who are you, where do you come from, and what’s your favourite hot beverage?

Petri: I’m a Finnish computing science student. I was born 83 in Kouvola (New Jersey of Finland) and right now I’m living in Helsinki. My favourite hot beverage… that’s a tough one. I drink a lot of coffee, but I have to say that my favourite is hot blackcurrant juice. It’s cool, because if you spill it, the stains look like blood splatters.

A 3 step tutorial

A 3 step tutorial

I’ve been playing the Crayon Physics Deluxe beta for a few of days now and I must say – I love the whole concept. Where did the idea come from… in fact where do all your ideas come from?

Petri: And I thought the favourite hot beverage question was tough…

In crayon there have been so many different influences, but the biggest conscious one has to be Crockett Johnson’s children’s book Harold and the Purple Crayon. After I heard about it, I started thinking how could I turn that into an interesting game. Crayon Physics was the product of that thinking.

Usually the ideas for my games come from many different sources. But I just looked back at the games I’ve done and noticed that a lot of late ones have been influenced by movies. So I could say that the ideas come from movies. But that’s only part of the truth; the ideas come from anything that I happen find interesting.

It seems you’re largely using open source and free software to develop the games. Care to share what software you use (in case anyone feels like following in your footsteps)?

A seesaw

A seesaw

Petri: The reason why I use a lot of open source code, is that there’s really no point in trying to do something someone else has done and allows you to use. Especially if you’re trying to do a game in a very limited time. Like I mostly do.

There is one bit of code that I quite frequently use, that isn’t publicly available. And that’s a game engine that I’ve coded. I use it mainly, because I don’t want to recode a sprite class every time I do a game.

As for the software that I use. I code in Microsoft Visual C++ (both 6.0 and 2005) and I use Photoshop for my graphics. Pretty boring stuff.

All of your games have very unique distinctive graphics. Are these your creations and if so where do you get the inspiration for them?

Petri: Yeah, they’re all made by me. The inspiration comes from various different sources. Usually it has something to do with the theme of the game. I surf through a lot of photos and try to find something that I can use in the game. Usually I just go, I’ll make it all black and white so I don’t have to worry about colors.

You recently released the first of this seasons prototypes, Bloody Zombies, another game that makes use of physics (albeit more simple ones). How did you fit so much blood into such small zombies?

Petri: Because the blood is all the same color I just used LZW compression.

Your games seem to inspire modders. Both Bloody Zombies and the original Crayon Physics prototypes have had graphics edited and even new levels made. Is this something you encourage (you seem to on your blog)? Do you build your games with this in mind or did it just kind of happen?

A weighted hammer to knock the ball to the star

A weighted hammer to knock the ball to the star

Petri: It’s half on purpose and half not. Usually I’m creating a game in such a big hurry that I really don’t have time to “think of the modders”. If I have to make the decision to do something fast or to spend more time with it to make it more available for modders, I’m going to go with the speed. However I use very open and easily editable file formats, so that’s probably the reason why there have been so many mods.

Also it could be that the games are so simple, that modding them isn’t really all that difficult or time consuming. Weird thing is I get a lot Mario mods… Don’t know why.

I assume that when you’re not making games, you’re playing them – so what games have you been enjoying recently?

Petri: I test a lot of different games, but I rarely spent more than an hour per game. Sometimes I do and I end up praising those games like a small maniac. Last addition to my compulsive praising list was Portal. It’s a small gem of a game. I highly recommend it to everyone. And I really mean Everyone. In fact I have started dropping hand made notes to random mailboxes that say: “Play or Portal or you will die in a week”. That’s just my way of supporting fellow developers.

You are currently developing one prototype a month whilst working on Crayon Physics Deluxe. Where do you find the time and motivation to keep going?

A car, about to get the star

A car, about to get the star

Petri: I wonder that myself. The one prototype per month is easy. They are so short projects that it’s more about finding enough time to do them, than about finding motivation. They practically do themselves once you get the ball rolling. No time to get unmotivated. Also if I don’t have enough time, then I’ll try to find something I can do in the time that I have.

Crayon Physics Deluxe is a different beast. Sometimes it’s a bit more difficult to find motivation to work on it. But I’m usually eager to do stuff, because I want something done before my next testing session.

Do you have any time away from the computer for real world stuff (eating, sleeping etc)?

My student apartment is so small that I really don’t have any other choice than to eat and sleep at my computer 🙂

Crayon Physics Deluxe is currently entered into the Independant Games Festival. Have you played any of the other games and what do you think your chances of success are? (fwiw I think they’re pretty good)

Petri: I’ve played a bunch of them, Cinnamon Beats, Clean Asia, Cortex Command, Dangerous High School Girls in Trouble!… There are so many entries this year and the most interesting ones of them you can’t play right now: World of Goo, Fez, Noitu Love 2.

Complex setup

Complex setup

My original plan was that I could probably get in to the finals through the student category, but that was before I saw the student entries. Those games are amazing, I didn’t know there are so many talented students out there. The level of quality in the student category is more impressive than in the real category.

So now I’m thinking I have better change in main category, but I don’t know. I’m somewhat pessimistic by nature, so if I make it to the finals I’m already a winner in my book.

Can you give away any sneek previews for this months Kloonigames prototype?

Petri: I haven’t really started it yet. I still have way more than 7 days still left 🙂

Thanks for your time, and best of luck with the IGF.

Crayon Physics Deluxe Walkthrough (Island 1)