Mega Man 9

- You're not that old, it's just really fucking hard.

- Have at least one E-tank before entering the last part of the game. Maybe two. Hell, get the maximum just to be sure.

- The hornet blaster is the best weapon in the game to easily run through levels with. The hornets home enemies and bring back powerups they drop (this means you almost never run out due to weapon powerups they grab) as well as any other powerups found throughout the stages (except E-tanks.)

- I have the easiest time starting with either Galaxy Man or Tornado Man.

- The only shop items worth investing in are E-tanks and the energy balancer. The 1/2 damage item is cool, but not necessary if you have the e-tanks, which are much cheaper.

- Do not buy the haircut or the Roll costume unless you are going for achievements that require them. They are huge wastes of money, and you take double damage with the haircut (no helmet)

- You can only hold 1 M-Tank, so don't bother saving up for several. Also, you can find one in Wily's castle, which is the only place you'd probably ever need it, so I wouldn't bother investing anyway.

- About Wily's castle: Unlike just about every other Mega Man game, there's no second skull in Dr. Wily's castle. Feel free to go nuts with your e-tanks when you get to Wily. Just be a little cautious since you still have to survive through 3 forms.

- My suggested boss order: Tornado-Magma-Hornet-Splash-Concrete-Galaxy-Jewel-Plug. If you have an easier time starting with a different boss, go ahead with that one but follow the same order after that.

Boss Weaknesses

The weaknesses aren't elementally aligned like you'd expect. Magma man is not weak to Splash Woman, for instance. The weaknesses are more practical than that:

Concrete Man is weak to Splash Trident because the trident can destroy all three of his concrete blocks.

Galaxy Man is weak to the Concrete Block since it freezes his Black Holes.

Jewel Man is weak to Black Hole Bomb because the BHB sucks up his shield.

Plug Man is weak to the Jewel Shield because it will block his plug balls.

Tornado Man is weak to the Plug Ball because it can travel up the walls to attack him when he's airborne.

Magma Man is weak to the Tornado Blow, since it blows out his fire (makes his attacks weaker, too).

Hornet Man is weak to the Magma Shot since it can take out all three of his hornets in one shot.

Splash Woman is weak to the Hornet Attack because it can kill her fish and keep going.

Splash -> Concrete -> Galaxy -> Jewel -> Plug -> Tornado -> Magma -> Hornet

Splash Woman is also the only boss that takes double damage from the regular Mega Buster, presumably because she does not have legs.