atari2600land has updated his maze/collecting item games GoSub, which has seen it’s initial release for Virtual Boy a while ago. Collect treasures with your underground boat in a maze!

There is also GoSub and GoSub 2 for the Atari 2600.

Release notes:

level 8 has been fixed. It was impossible to beat.

http://www.atariage.com/forums/topic/147240-gosub-for-virtual-boy/