“Hex Tweaks” are loosely defined as sets of single-or-multiple-byte-changes that can be preformed for desirable effects. There is no clearly-defined upper limit for the number of bytes that can constitute a 'hex tweak' but they are usually less than 16 bytes' worth of changes.

Tweaks for the mechanics of Samus.

0x1C2A - 01 to 02
Samus runs faster to the right.

0x1C6D - 01 to 02
Samus runs faster to the left.

0x1C99 - 02 to 03
Morph ball rolls faster to the right.

0x1CCA - 02 to 03
Morph ball rolls faster to the left.

0x1CFB - 01 to 02
Samus moves right faster in air.

0x1D27 - 01 to 02
Samus moves left faster in air.

Tweaks for beams, missiles, and bombs.

0x51A1 - Everything up to 0x51C1 becomes 04
Makes missiles fire at a faster and more consistent speed.

0x53FC - 60 to ??
Changes the amount of time it takes for a bomb to explode. Change this to 30 for Super Metroid's bomb explode time, or 20 for Zero Mission's.

Tweaks for energy and missile drops.

0x8270 - 05 to ??
Changes the amount of energy an energy drop will add.

0x82AC - 05 to ??
Changes the amount of missiles a missile drop will add.

Tweaks that don't quite fit in with any of the particular categories.

0xAA43 - 05 to ??
Changes the amount of missiles it takes to open a hatch.