#26 was the Battle for Wesnoth, which nobody got. Better luck with the next games.
#25: Guessed by The_Liquid_Laser: Starcraft/Broodwar
#24: Guessed by OTBWY: Supaplex (Infotron is the Mac-port)
#23: Guessed by Landale_Star: The Legend of Zelda: Majora's Mask
#22
a) Gameplay switches between real-time strategy building up your bases and turn-based fights.
b) The real-time part presents you with the earth in globe view, with the possibility to rotate and zoom.
c) Recruit your soldiers from all over the world.
#21
a) This entry of the long going series actually sold the most.