UltraMario
Donkey Kong
I prefer to search every nook and cranny for enemies to defeat, items to collect (example: coins, rings, star bits, etc.), and extra lives. Even when it comes to Sonic games I stick to this preference, which is ironic because speed is the franchise's main gimmick. However, some games have you timed in a level (example: 2D Mario platformers, 2D Sonic platformers, etc.) which makes it difficult to do the things I mentioned previously.