Glitch hunting this game a little on J.
Health bug
When you die and start a dialogue at the same time, your health can deplete to zero but you won't die. This gives you 128 health points.
Timer exploit
If the depletion of the timer falls on a paused or a lag frame, it will be skipped. This means you can go anywhere even when you have no time left. Dialogue characters can not be bypassed, it seems.
Revisit stages
Was already known. After beating a stage and closing the score screen, the level selection will open and the first stage will be selected by default for 1 frame. This means you can play the first stage again even though you beat it. If you collect the key item again, the game will go to the level select screen immediately rather than award you points and go to the score screen first. The BGM might get messed up, even through soft resets.
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Addresses (system bus):
$ca1c (1 byte) health
$ca10 (1 byte) timer minutes
$ca11 (1 byte) timer seconds
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