My thoughts would happen to be Sonic the Hedgehog, Sonic Heroes, Sonic Unleashed.
Sonic the Hedgehog is the very first game it played and looks too Basic to make this game the best for a little difficult challenge by gathering all 6 Chaos Emeralds, also the Boss is always Eggman with his good start inventions to battle Sonic for an increasing challenge.
Sonic Heroes is the game that you could have team to work together on the adventure and it have some Zones to complete while gathering all the Chaos Emeralds in that Area, good Team Work Elements and good characters to know where they might be able to beat the Zones more simple.
Sonic Unleashed makes one of the most fastest game to enjoy in every location of the world to complete at. Sonic the Hedgehog could be best of running to the Goal and more view to be impress about. Sonic would also transform at night for fighting enemies into action and even mostly took all the missions it might do to simply beating Bosses.