NikiTo said:
If you hobby game is of interest for your game company, they can take it. You can bet on it. It will be not a matter of morals. Not a matter of “did the employee steal the idea or not”. It will be a matter of court's decision.
Don't know which country you live in but in Euroe this is highly regulated and some countries especially have a very restrictive law about ownership. The clause “we own all your work” is often added into contracts but isn't valid in any circumstances. Stuff you did outside of your working hours and ourside of your day-to-day tasks are not covered by this clause. If you fix a bug outside of your working hours in code that is related to your day-to-day job, this counts as work implicitly and so falls to the “we own all your work” clause as well regardless. It doesn't matter when you do it, it does matter what you do.
This is why game companies have those clauses “ you shall not do something similar to what our company does” in their contracts, which is absolutely legal (in my country). This ‘no-competition clause’ is a protection for the employer to not spend his money to the employee who in the end takes all the knowledge or even customers to sell his own work to them for a higher pay rate as the employer offers. There should be no discussion about the sense of this clause at all!
But even employees are still humans (even if some companies think different about this topic) and so humans are free of speech and opinion. This also covers knowledge, work and ideas they do outside of their working hours and not related to their work if commercial or related to their work if uncommercial is also completely valid. If an emplyoee writes a story for your game and instead takes the good ideas for a book, this is valid because he/she is free in his/her speech and opinion. You can't do anything about it!
Btw. asking people for their hobbies and don't hire them if they do something similar in their spare-time is illegal in my country. I'm honest at this point and I also don't offer everything of my ideas and knowledge to my employer. This is for a simple reason, I invest my spare time to gather that knowledge and the company isn't paying for it so they don't get it. But to tell the whole story, my company is fine with my after-work-work.
On the other hand is it a benefit for an emplyoer to hire people that do hobby projects of the same kind or at least in the same field as the company theire hired of because people tend to bring their knowledge into the company if they feel valued. A problem at work can be solved from experience gathered from a hobby project and both parties benefit from it.
However, even in my country you have to ask your emplyoer to start a secondary career besides your working hours. This is not to block people from having theit hobbies but again to protect the emplyoer paying for you and to ensure you're not spending more working hours into your own stuff than into teh contratced work so that your contracted work suffers from it in the end.
@zansin if you really want to get sure that nobody can steal your work, you should place it in a public spot like GitHub and add a propper license to it. AGPLv3 for example is a good one as it forces everybody to publish work that is based of your work to an also public spot. So if your emplyoer would steal your work and you can proof it (which is very easy as there are services to compare code bases used for example by universities to proof plagiarism) it would force the company to publish all their source code and this is something they don't risk at all. That's why IT companies are very strict in checking a source's license before taking just a piece of it
