Do you need Giants to beat Skylanders Giants for Wii, or can you just use regular Skylanders to beat the game?
I've played the game through; while there are some things that only a Giant can do, there's also always been a way to either do it with a normal Skylander or bypass that section of the game.
So, technically, I don't see that you absolutely NEED a Giant to play the game. It's just really geared towards you having one.
As an example of alternate ways of doing things: the walls that giants can break through can also be blown up in 'the usual manner' with a throwable bomb. And there's always a bomb around when there's a wall in your way.
As an example of things that you need a Giant for but aren't completely necessary: there are rocks that only a Giant can pick up. Sometimes there's something underneath the rock. Sometimes it's a hole that leads to another part of the game that is only accessible that way. All of these areas that I've seen have been optional though.
So you won't get 100% completion without a Giant character, but you should be able to finish the game.
You can beat the main quest of the game without a giant, but you need at least one to access some special areas of the game, just like you can beat the game without a character from each of the eight elements, but you can only access certain special zones with the correct element.
you don't need a giant to finish the game only when you see a sign of tree rex that's when you need a giant but when you see a bomb and a giant and your using a small skylander then you can go and find a bomb come back to the wall and throw it or you can switch to a giant and smash yor way through.
Yes, you must have a Giant character to complete the game.