None of my games guessed so far, so I should add a hint before going to sleep.
#50
a) Turn-based or real-time? I can't decide in this newest entry in the series.
b) This europa is a bit different than europe.
#49
a) Six degrees of freedom!
b) Robotic helpers gone crazy and taking over.
#48
a) Build towers out of people.
b) Level up crazy much.