Mega Man X2/Heart Tanks

Overdrive Ostrich
Get the Speed Burner, the Leg Upgrade and the Arm Upgrade. Near the end of the stage, you see a Heart Tank sitting on spikes, stand just before where the spikes are, charge up the Speed Burner, and then do the air dash, and finally release the Speed Burner to get the Heart Tank. You will die after getting it. Death can however be avoided if Ostrich is already defeated; pause the game just before landing on the spikes after getting the Heart Tank, and use the exit module.
 * Method One

Ride the motorbike over the entire desert section of the stage. When you get to the end, making sure you are holding the dash button down the entire time, shoot down the last ramp and you should go flying to the upper section; there is one more ramp to shoot down. If the bike breaks, you can backtrack and find another one halfway through the desert section. Try not to shoot too much; it causes lag which lessens the chance of making the jump. Just keep trying and remember to hold the dash button and that pressing the jump button is not necessary at all. Once you get inside ride over the spike section and retrieve the heart tank. If you time the turn properly, you will succeed in retrieving the heart tank without dying.
 * Method Two

Wire Sponge
At the beginning of the stage, climb up the left wall.

Wheel Gator
You will see a Heart Tank, but you cannot climb up the wall due to the spikes.

Get the Speed Burner, Leg Upgrade, and Arm Upgrade. Stand on the higher ledge, charge up the Speed Burner to the left, do the air dash, kick off the wall just above the spikes and get the Heart Tank.
 * Method One

Simply dash jump and use the charged Speed Burner to kick off the wall above the spikes.
 * Method Two

Bait the robot to the right of the Heart Tank to attack, and get hit at the end of the bullet animation. You can use the invincibility frames to wall jump up the spikes. If you have the arm upgrade and the Crystal Hunter, you can charge it to slow time down, effectively giving you extra invincibility frames. If not, try to get hit so you fall down to the level next to the spike wall.
 * Method Three

Get hit by the enemy ride armor at the top of the ladder proceeding the Heart Tank, and use the invincibility frames to wall jump up the spikes. This method is generally only useful for speedruns since method three is easier.
 * Method Four

Get the Strike Chain, then use it to obtain the arm upgrade in Wheel Gator's stage. Go to the right and hop on the 1st platform. Charge up the weapon, then dash at the wall and in the middle of the dash, release the charge. Jump at the edge of the platform toward the wall. If you're lucky, it will hit the wall behind the container with no risk, more likely, however, it will hit in front of it and you will have to jump up the wall to avoid the spikes. Be careful, if the chain hits the spikes you must immediately cancel it, so you do not die. This is the hardest of the 5.
 * Method Five

Bubble Crab
A little after you see the fish-looking submarine for the first time, scale the wall to the right of the large trapdoor the sub opens. Climb to near the top, and then dash jump off the wall leftwards to reach an orange rocket platform. This may take a few tries. Scale the wall it goes up to and get the Heart Tank.
 * Method One

Get the Speed Burner and the Arm Upgrade. Charge up the Speed Burner to make some extra horizontal distance. This makes the dash jump to the orange platform a little easier.
 * Method Two

Get the Bubble Splash and the Arm Upgrade. Charge up the Bubble Splash to make your jumps underwater higher. This makes the dash jump to the orange platform a little easier.
 * Method Three

Flame Stag
As you scale the erupting volcano with rising lava, quickly destroy the wall enemy to the left to get the Heart Tank. If you have it, the Spin Wheel can destroy the wall faster.

Morph Moth
Get Crystal Hunter. At the beginning of the level just before going indoors, freeze the disk-throwing enemy, use him as a platform, dash jump, climb up the wall, and get the Heart Tank.
 * Method One

Get the Leg Upgrade and Arm Upgrade. By utilizing the infamous 'Neon Jump' trick (jump, then air dash, then jump and release the second charge shot at exactly the same time; on the same frame) you can reach the wall without the Crystal Hunter.
 * Method Two

Get the Speed Burner, the Arm Upgrade and the Body Upgrade with a fully charged Giga Crush. From the indoor section with the roof magnet, charge the Speed Burner, jump, release the Speed Burner to fly just a tiny bit past the wall outside, pause and switch to Giga Crush, use Giga Crush to get a tiny bit more height, then turn around and grab the wall to claim your prize. You only get one shot at this, you'll have to recharge the Giga Crush if you want to try again.
 * Method Three

Magna Centipede
Early in the stage, get past the yellow spotlights. If you get detected, don't destroy the last security bot turret that falls from the ceiling. Run ahead to the first giant 'crusher' block, then run back to respawn the bot back on the ceiling. It won't respawn if you destroyed it. There is a vertical shaft just above to the right of this bot on the ceiling. Run next to it, a few pixels off, neither too close nor too far, then jump, then press jump again without touching the directional buttons/analog stick to get X to kick off the wall. Then simply wall jump up and claim your Heart Tank. Remember: You need to be at just the right distance and not touch the directional buttons/analog stick; X can wall kick off walls higher than usual more easily if you don't hold the direction of the wall you want to kick off of. Most people don't even realize you can get the Heart Tank this way and think method two or three are the only ways.
 * Method One

Get the Speed Burner and the Arm Upgrade. Avoid touching the yellow lights. Stand on the higher ground between the turret, and the giant 'crusher' blocks, facing left, charge up the Speed Burner, do a dash jump, release the Speed Burner and climb up the ceiling gap to get the Heart Tank. Again, if you got caught by the lights earlier, go ahead to the right a bit and go back to respawn the turret.
 * Method Two

Get the Speed Burner, the Leg Upgrade and the Arm Upgrade. Repeat method two, except air dash prior to releasing the Speed Burner for an easier jump.
 * Method Three

Crystal Snail
At the beginning of the stage, get in the Ride Armor, head left back up the ramp, and fall left down the fake bottomless pit to a platform. Do a dash jump to the left, tap the jump button semi-rapidly (~3-4 times per second) to extend the armor's flight time, dash jump out the Ride Armor just as it's about to fall into the abyss, and finally land on the platform to claim the Heart Tank. This may take practice.
 * Method One

You can also more safely get the Heart Tank using the Strike Chain to grip the wall at the end of the jump; you won't have to do this if you executed method one correctly, however it is nice insurance to have and you can actually make the jump this way by holding the jump button without the semi-rapid tapping.
 * Method Two

You can also more safely get the Heart Tank by utilizing the extra air the Giga Crush attack gives you at the end of the jump.
 * Method Three