Here are some more clues to my games:
50 a) This GBA game is based on a very old Japanese manga.
b) The protagonist is both a robot and a boy.
49 a) I will be surprised if anyone gets this one, so here's about as easy as I can make the clue. This is an early 80's arcade game where you extend your tongue through a maze to eat pellets as well as ants and worms. At night a spider comes out, which is almost impossible to kill.
b) There was a clone of this game called "Aardvark" on the Atari 2600.
48 a) This may be the best looking (and best overall) 2D game on a console known for 3D games with now very dated graphics.
b) The protagonist's name in this game is the main antagonist's name spelled backwards.
47 a) This is an early 80's arcade game known for using a trackball to shoot different bugs.
b) If you are thinking of two possible games, this would be the first one.
46 a) This game makes great use of the Wii U gamepad by allowing one of the players to split up and still have their own screen.
b) This game uses well known Nintendo characters, but was not developed by Nintendo.