Tip: When determining a time limit, remember that players won't be as familiar with the level as you are. If you normally complete the level with the timer around 100, others might run out of time on their first try.
The sprite<->tide interaction code is messed up in the original SMW. While the original levels never seem to run into this problem, you can find it if you e.g. place some floating platforms (5B through 5E) in level 102 (they will randomly start to levitate). This patch fixes this bug.