Is game mechanics copyrightable?

You can copyright your rules and visual pieces (cards, game board), but not the name or branding. The name would need to be protected by a trademark, which is very different from a copyright.

You also need to be careful not to copy the specific rules of another game too closely, or you may be infringing upon their copyright. With the Uno example, you would be free to make a game based on the concept and system of crazy eights (which is in the public domain). Just don't go too far beyond it in the same direction as Uno (using cards specific to Uno like "Wild Draw Four" etc.).

OK, I guess I need to give a little explanations now ;) .. First, I didn't meant to literally photocopy all tiles, I meant to ask about using the same action and similar icons ...
I found yesterday on a boardgamegeek a list of games that are in the public domain ... and that triggered the question, because I was sure that I read somewhere that name can be protected via trade mark, but that game mechanics can't ... That's why I posted the question in the first place ... I remember seeing a picture of patent registration for Magic the gathering in one of the Levy's book about inventors, but I thought that he wasn't right completely because there are so many TCG's now with very similar mechanics like magic ... then zaiga posted info about Magic being not 100% protected ... then I posted my old idea about rescue crawling game which I planned to do in similar fashion like Drakon and other crawling games but with different tiles and rules ... it's easy to add a couple of pieces to the game and to add some rule changes ... but I wanted to ask about legality of realy copying the whole mechanics, each tile even, because who can tell where the line between game similarity should be drawn ...

Now, let's assume that dominoes are not in the public domain ... and I want to make a Disney version of dominoes with disney characters instead of matching numbers ... dominoes rules are so simple, I mean it's 1 line ... would it be unfair to do the disney version? Or I'd need to reconstruct domino tiles into some Tetris like shapes, so no one can be upset with my change ...

I think the scope of what you're trying to do and the degree to which it is acceptable (at least in my eyes and very likely others on this site) depends on your treatment of the game.

There is a vast difference between borrowing a mechanic here and there and wholesale lifting of another designer's game design. Think of it as a recipe. Lots of recipes have onions in them, but that doesn't make them the same. Each has its own flavor and texture. Yes, presentation is important, but you can't just take someone else's soup, put it into a new bowl and call it your soup. You can freely use ingredients found in other games, just make them your own. Find unique ways to incorporate them.

You mention both that you want to incoporate various mechanics from a variety of games into your own game, and also that you want to "copy whole mechanics, each tile even..." I don't have a problem with the first so long as you make the game your own. Use a mechanic here and there, but put them together in a way that gives a new gaming experience. Bravo and good luck to you to that end.

The other, however I cannot condone. Like others, I would disuade you from lifting a completed game from someone else and slapping your own theme or designs onto them. Depending on the game, you may be in legal trouble for doing so. Copyrights protect the method of doing something. If your rules are demonstrably close to pre-existing game (irregardless of the theme or icons), you could find yourself in legal hot water.

It is always better to make your own game. Use mechanics that you like from different games, but use them sparingly and make them your own.

Well, first of all, I haven't said that I plan to copy any game, all questions were hypothetical ... I said that I had an idea about rescuing game using dungeon crawling mechanics and nothing else ... All questions were triggered because of the list of games in public domain, which I understand as meaning that anybody can print those games with exactly same rules and with exactly same name (chess, dominoes and such) ... and then I simply asked about game mechanics copyright ... so, I guess, no one knows for sure whether game mechanics can be copied or not ... I agree with last poster that it would be stupid to simply lift all rules and re-theme it, although the result can be much better then original, i.e. if original game was targeted to very narrow gropu of people (gothinc theme, nerd theme or something similar) and someone sees the possibility to apply same rules to some other common theme ...

Interestingly, Monopoly started as localised versions, with players visiting friends in other cities and then re-theming it when they drew their own board to use at home. It just got locked down when Darrow "his idea" to Parkers.

I recently saw a c.1900 copy from Delhi, which seems to have been done by an individual after trying the game in America.