Note: all demonstrations need Snes9x v1.43-improvement9 and preferrably SMR v2.1-headered (but will most likely sync on all the earlier versions).

Using the combination of stutter-walk (see shortest charge) and a workaround for running distance check, it's possible to achieve full boost in only 363 (381 after complete stop) pixels, as opposed to the usual 479/501 (demonstration). Up to 120 pixels of distance are reduced this way, allowing for some useful applications:

The travelled distance check used to grant Samus the final boost counter increment allows four frames of non-dash while still retaining the lowest running time, which allows for such reduction. In other words, you should release dash for 26th to 29th frames of running and press down on 101st.

After recharging on a slope, Samus doesn't get her full running momentum immediately, which allows to initiate a spark without prior crouching, even in mid-air while jumping at boosted speed. The window of opportunity is very small, though: only 14 frames. This can also be used to slow down the spark a little without entirely stopping or cancelling it.

Demonstration.

The "slide" observable after crouching at high speed can be reduced if recharging on a slope. To do this, you need to press forward + dash + L or R at the moment of recharging to go into running state, then down + dash + L or R on the next frame to store the charge, and L or R without any other buttons on the next frame. This can be used to cut off 18 pixels off the sliding distance.

Demonstration (compare to the usual sliding distance under same timing).

Springball doesn't check if Samus is on the ground to initiate a jump — only her vertical speed. By placing one or two bombs, letting them propel Samus and pressing jump when her upward acceleration reaches zero, you can successfully extend her jump height by about two full tiles. Obviously, it also works with any amount of bombjumps prior to springball jumping. You can't do double springball jump in this fashion, though.

Demonstration.

Note: this trick also works in SM, but due to SMR's level design and physics, it's actually useful here.

Unmorphing during IBJ slows down the fall, allowing a necessary leeway for such things as continuous IBJ through water or lava. The common aplications are:

Quickly alternating spinning and unspinning when jumping with prior dash, it's possible to keep the speed while temporarily reducing aerial momentum. Changing from standing jump to spin resets it, so by doing it on each second frame, Samus's average momentum can be brought to a mere 0.24576 px/f, compared to 1.24576 (spinjump or falling state) and 1.16384 (standing jump). This can be successfully applied in circumstances requiring you to jump down at low speed to clear a low ceiling.

Demonstration.

To compensate for increased gravity in SMR, Samus's jumping strength was increased accordingly — up to 10 px/f without a prior speed boost. That messes up block collision checks during the upward movement, and thus allows to jump right through some thin ceilings.