Many levels feature hidden coin rooms or bonus areas that can be accessed via secret pipes or vines. These areas are usually filled with coins, providing an excellent opportunity to rack up points and earn extra lives (100 coins = 1-Up). While not strictly 'side quests,' finding and clearing these rooms is a rewarding activity. For example, in World 1-2, if you don't take the Warp Zone, you can enter several pipes that lead to coin-filled underground sections. In World 4-2, the vine to the Warp Zone also leads to a cloud area with many coins. Always explore pipes that seem out of place or vines that appear from hidden blocks, as they often lead to these lucrative bonus areas.
