Why does my game gear not move right?
Why does my character always move to the right even when i am not touching the control pad?
The Sega Game Gear portable gaming device was released in 1991 in competition with the Nintendo Game Boy.
I'm not familiar with the insides of the game gear, but like R Trent says it does sound like the d-pad may be worn out. Open it up and look under the hard plastic d-pad. Controllers use a contact that conducts a signal via a carbon-impregnanted pad attached to a rubber cup that acts as a spring for the button. The rubber may be broken so the pad can't spring back causing this constant right press. Fortunately, many controllers use the same d-pad setup. You can probably get a cheap controller and replace the rubber cup setup in your Game Gear. Use this guide to help you open it up.
NOTE: from what it looks like it also has a 'Gamebit' security bit, but if its 3.8mm you can probably get away with using a 3.0U Spanner to open it up.