I've beaten this dude twice, barely. He gives me trouble. So I want the experts in the game to give me some tips on how to beat him. Obviously, you want to start off with the player you are most comfortable with to defeat those 2 silver surfer dudes (yes, I'm a noob) while building up your hyper combos. What's next after you've taken them down? Of course, I want to be able to beat him with different characters to see the endings...
If you're playing on one of the Easy modes, you can spam Hsien Ko's crouching-claw-slide thing on the cosmic clones. I've taken them both out while only taking two or three hits on multiple occassions this way.
Galactus I've found you just have to take cautiously. Try not to be on the ground too long, and watch his hands to see if he's about to attack. If he leans away and starts to clap you, you need to super jump--a regular jump won't clear a safe distance and you can't block it.
Basically on phase 1, combo the crap out of the first guy, when the second hops down, make sure you're on a projectile super character and blast em both (double chip or double damage) otherwise the armor'd one will eat you up since he likes to get behind you.
As for Galactus... just defend on any swipes flicks until the second you see/hear the impact (game generally hangs for dramatic effect on the hit) and simply get him have it, two L1 supers will generally knock him out of his instaKO mode... super jump when he strafes to the background to grab and most characters air supers will hit him while he's under you and as he sets back infront, with no sound and lag from a capture card I still had a character up.
You are remembered for what you did, not for who you were. Do something, don't just be somebody.
I'd be interested in hearing a little advice, as well. I'll give some here, but bear in mind that I'm average at best myself... i usually go in for 3D-type fighting games like Tekken and DOA that don't move at the speed of light.
I actually only just read online that when Galactus palms you between his hands, you should madly tap buttons to get him to release you. Good to know, that move seemed unfair, as there's usually no good way to avoid it. I have managed to get above it once or twice by activating characters with flight who have that option.
He also has the one attack where he charges up for freakin' forever, then unloads and basically insta-kills whichever character is unlucky enough to be on the field at the time. Just be sure to bring in your weakest, or most beat-up character when this happens to be the sacrifical lamb.
Other than these two attacks, everything else is actually blockable as far as I can tell. Play defensively... block until he's finished his attack and then unload on him with level 1 hypers. Generally keep away from team-hypering, as the danger of his hitting both your assist characters is pretty high. Also, keep in mind that some of his attacks come in strings of two or three... for instance, when he slaps the group, he usually does it two times in succession. Wait until the second one to use your hyper, or he'll catch you with the second attack and interrupt you. When you run out of hypers, I generally try to throw projectiles at him until I've got enough meter to unload on him again.
That's about all I got after playing this game for a single day. Hopefully others will have more helpful hints.