Unlike screen constrain, this patch constrains the player and sprite's interaction with blocks within the level (properly, check out the first gif to see why).
V3 update: Now works properly with LMv3.00 dynamic levels patch.
Tester's Note: Does not work with Morton, Roy, Bowser, and Reznor.
3.1 update: now you can disable the patch's effect via a RAM if you want to have only specific levels not to have this effect.
3.2 update (removed because crashing): freeram is now bit-side-based, to make disabling each individual of the 4 sides possible.
3.3 update: fixed potential crashing issue.
3.4 update: fixed a bug that Super/Cape/Fire mario, when not crouching, interacts with the 2nd-bottomost row when he should only interact the bottom row. It now uses fastrom (happens when JMLing back to SMW code).