In most basic terms, what I would say is that its only a good idea to invest in a company if you're reasonably certain that things are going to go well for them long term. See: cannabis in Canada. Lotta people made a lot of money by taking the governing group in Canada at their word and investing in weed a year or two ago when it was getting cooking. That easily could have blown up in their faces if the liberals had lost majority, favour or just said fuck it - the money would just be gone with no recourse. The other example would be tesla, where shit got super real for a while, and if you believe the interviews with Musk it easily could have all exploded just a little while ago. Nobody wants their livelihood riding on crazyness like that - particularly when you have shortsellers actively working to increase the odds of a failure so they make some money. Seriously, look up "prominent shortseller says..." and then line it up with the companies stock value. They say shit specifically to spook people so they can make a buck.
The actually publicly traded game companies generally also have gads of subsidiaries that you need to know about before you can make a call on their future prospects - sony has like a dozen subs ranging from tech to insurance, as opposed to activision which has maybe ten difference game studios. Its one thing to say "I know when COD comes out activision will see a little boost" but first, that isn't impressive knowledge because everyone knows it, and second, what the other subs are doing will still have an effect on the overall stock value, so if they're sucking shit then your COD bump will be mitigated. Add on to that the fact that "a little bump" from a game being released is day-trading AKA idiot gambling (it has worse odds than just going to a casino) and you can't depend on it long term. I work with day traders - those guys are nuts, and they spend most of their time frantically tracking and working their stocks to make money. Some of them do well for themselves, but considering I work 40 salaried hours per week and get paid even if things get rough for a month or two, while they work 80 and get fucked if things dry up, I feel I have the better deal.
Overall, I don't know if I would suggest investing in an entertainment company long term. Getting in on the ground floor of a company that ends up becoming a stand by (you may not love activision today, but if you started investing the moment they went public you would have made a tidy sum) is awesome, but it requires you to basically predict what is going to be popular and whole companies dedicate their every moment to doing that and still can't get it down. If you new that fortnight was going to rule the world of a bunch of 8 to 16 year olds you could have made some bank on that, and if you feel that the epic games store will be successful now might be a good time to look at tencent, but personally I prefer to put my money in long term funds. I'll never get rich that way, but that's why I have day job - all this shit is extra cash for traveling for me.
If you want a hawt teep, CN may be worth investing in - they're developing technology (its in the news, this isn't insider) to ship crude oil more effectively and safely to the coast, so we can cut the influence of the volatile US market. Of course, this is going to take a year or two, and in the meantime if a certain pipeline comes through this whole scheme will get shittered. Feel like gambling?