The Syria discussion reminded me incidents in the past when some video game company sued or at least legally threated another game company because their game reminded the original game too much. Games like PacMan (and the variants) and Super Mario Bros vs Great Giana Sisters. I think those claims were successful too, blocking or withdrawing the release of some releases (e.g. "Jelly Monsters" on Commodore VIC-20, and "Great Giana Sisters" on Amiga).

I don't recall hearing about such claims for a long time, have there been such anymore after those 80s incidents? If not, what happened? Did the legislation (in US) change, were there later too many unsuccessful claims, or the game publishers just somehow wisened up and all started copying ideas from each others?

I wonder if you could still patent game ideas the same way you can (?) patent e.g. ideas for user interfaces (triple-clicking and whatnot)?

I think that problem might be that there aren't any "real" innovations anymore. Everything has been done and done again. Unless you are directly using an IP that belongs to someone else (Ubisoft doing a DA:O Beachvolleyball game) the risk of a costy litigation is probably to high.

And I think it has something to do with a cerain, don't sue me, I won't sue you attitude. There is just to much money at risk for to little gain to be made.

However, that doesn't stop the big guys from legally curb stomping fan made mods or indie devs that are infringing they copyright. (Again, that is why my DA:O Beachvolleyball game hasn't been released)

Could be. I wonder if e.g. mobile devices will enter a similar state at some point, ie. Apple and Samsung will not keep suing each others because their devices look and feel too similar?

I only remember one clear case where this happened in more 'recent' consoles and pc-gaming. Okay Crazy Taxi isnt THAT recent but not 80's past like you mention.

Where Sega (Crazy Taxi) sued Fox Interactive, Electronic Arts, and Radical Entertainment for 'The Simpsons Road Rage' and was settled privately out of court in the end. Road Rage wasnt actually that great but the GBA version actually knocked the Crazy Taxi GBA version out gameplay wise.

And the big case: Bethesda against Mojang because of the word "Scrolls"?

In the good old days, lots of coding where done by bedroom programmers and small independent companies (and they ripped each other off a lot...). Today it is large conglomerates with corporate lawyers making sure no-one steps on anyone copyright early in the process.

Now the bedroom coders are making homages and re-makes instead.

There's that Chinese TF2 rip off called "Final Combat" that Valve put a spotlight on Steam last year, but I doubt they have the ability or desire to go after it. There was a Korean one too, but I don't recall what it was called. They used purdy anime gals though for character models.

Good call, albeit that may be more about protecting their name brand, not a game idea, or look or the feel of the game.