I'm making a freeware game. Right now I only intend to make money off of donations. If the game gets popular, I might grant special items for a price, but that would be server-side anyway. I don't want people to modify the code to cheat or make their own game, but as I understand this is already protected by my inherent copyright. Other than that, since the game is freeware I don't need/want any restrictions on distribution, so is there any need for a EULA or something similar? Could I just put the game up for download no strings attached, or is there something I should be worried about?

are you planning on paying all the money required to sue people who break those rules? if not, and if people aren't paying for anything then an EULA likely doesn't get you anything because you're not going to enforce it.

if you're actually concerned about it, hire a lawyer to answer your question. You'll need to retain a lawyer to write the EULA in the first place anyway.

-me

A lot of freeware programs (and games) do use EULA, often to prevent others from "selling" the software and to specify how it can be distributed. Also the usual "This software is provided as is so if it crashes your system it's not my problem :)"

I suggest looking at a bunch on existing software to give you some ideas of what you can include. Of course you will still need a lawyer to write it up but if you already have a good idea of what you want to achieve it will make the process clearer.

These things are protected by copyright law, but it is good to clarify what people are allowed to do with your program (so they are allowed to distribute it, but they mustn't distribute a modified version, for example).

And yes, the usual response in these forums is "You need a lawyer", but I can't help feeling that is less than practical when someone is writing a game for free. Would it be possible to use an existing licence? There are plenty for open source (GPL etc), are there any for closed source freeware I wonder?

Here is a good list of existing software licenses. It will be much better if you can find an existing one rather than write your own.

I think you are dismissing an open source license fot the wrong reasons though. If your game is not an online game, why do you care if people cheat? Very few of your users will want to, (or be able to) modify your source code. Those who do will enjoy your game more if they can.

Also, if people make their own game based on yours, and give you credit for use of your code, why will that be a bad thing? Under the GPL, their code will have to be open source as well.