So it's finally time for me to join this thread... I'm way behind, but here's a dump of some hints. I'll try and guess some other people's if I get chance too!
#50 - Arcade port, first game in a franchise which released with the launch of every single console from one of the big three... until last year. (guessed by artur-fernand)
#49 - The previous game fully established open-world as a mass-market thing; the sequel ran with the idea and blasted it into the most fantastic setting imaginable, with a killer licenced soundtrack. (guessed by artur-fernand)
#48 - Prior to creating this open-world adventure starring an amnesiac girl, the development "studio" had worked exclusively on a horror franchise for more than 5 years. (guessed by soulfly666)
#47 - (this'll be a tricky one). Long running "racing game" series which received a duff entry on the PS2 only to be revived on the PSP. This is the entry that followed that PSP rebirth. (guessed by artur-fernand)
#46 - Released as a 10th anniversary celebration of this JRPG series, the 5th numbered entry and currently last entry in the series (not counting a spin-off)
#45 - Kitty Kibble shortages and broccoli everywhere.
#44 - A game featuring the original bastards - one who told you off for quitting without saving; the other a massive money-grabbing twat. This was the original that was tile-based, unlike its successors. (guessed by Wright)
#43 - After swapping green lands for a murky city, this second sequel traded both of the above in for the desert. Featured a "wizard of oz" esque ending.
#42 - First person platformer starring a robotic rabbit. There can only be one. (guessed by soulfly666)
#41 - The final boss of this fighting game was a young woman who beared a startling resemblance to a missing character... who had been possessed by a phantom spectral wolf.
#40 - Hands down the best Star Wars game ever made; the sub-series is finally being revived soon. (guessed by artur-fernand)