gameboy games eat away battery?

ive had my gba sp for a few years now (used from flea market) and it has definitely less than normal battery life but has never given me issues with gen3 pokemon/mario kart but recently i started playing pokemon blue and gameboy tetris (original cartridges) and the battery starts flashing red after only 30-45 minutes? does playing gameboy cartridges with the backlight on usually take up more battery power and/or is it possible to easily upgrade/replace the battery?