Game has a mix of mega evolutions and regional variants. Mightyena variant becomes dark/ground. Garchomp variant becomes grass/dragon. Some new megas I know of are Mega Luxray, Mega Haxorus, and Mega Cryagonal. The game itself feels like open world but much smaller than Paldea. Majority of it takes place in the urban areas of Lumiose with some underground areas. Time period is present day and the game is expected to come out early Q4