Katamari top right. Gunstar Heroes weapons on the "Massive Damage" sign far left. A tiny Megaman to the left of the Mushroom Kingdom area. I don't see Sonic, but I do see Green Hill, so changing tag to refer to the game unless someone can point out the character. Is definitely a cacodemon; so tagged.
loco roco bouncing next to the parappa the rapper stage, cloud's out in front of the castle, and the ape's from ape escape are poking their head's out of the pipes next to him along with the rabites and mushbooms around the castle (from secret of mana)lara croft's standing and waving behind the van next to the tetris stack.... ummm... any more anyone can point out?