Don't have this setup anymore, but I once had a PS2, Atari 2600, 5200, NES plus a VCS paddles plug-and-play either all connected to the TV or on standby for switching around.
Just as a trivia note: Atari stopped packing paddles in with the VCS right around the time they started marketing it as the 2600 and adopted the Vader look. By the time the 2600 Jr. came along I think they only included one joystick, kind of a dick move considering how many two-player-only games there are for the console.
I have to admit I respect Adventure more than I enjoy it. Don't know much about Secret Quest, but I do know as far as adventure games on the 2600 are concerned, I'll choose Pitfall II over Adventure most of the time.
I feel your pain. Even with KaeruYojimbo's good advice above (thank you, btw) I still feel like I'm doing everything at random. It's really hard to visualize the movement of the blocks. I'm used to using my imagination with the Atari 2600 but this is a little much.
Getting so frustrated with this game. Control is terrible and you get hung up on walls way too often. I've even tried strategic dying to keep most of my scoring on easier levels but that doesn't help either. I miss Seaquest, and for that matter any game designed by someone who knew how to make a game (primarily one with smooth controls and a difficulty level that scales reasonably ie. almost anything by Activision).