Mortal Kombat

For this one, you have to GET PAST challenge 300: Endgame. You can skip it for 50,000 koins if you wish, but you're going to need to beat it at some point anyway, so here goes:

The character you choose is entirely up to you. As you may know, Stryker is my preferred character, and since the majority of his attacks are ranged, he's one of the most useful characters for this challenge. However, if you're really good with someone else, then use them as you please.

In this order, you fight Goro, Kintaro, Mileena, and eventually Shao Kahn himself, ALL ON A SINGLE LIFE BAR. This is far from easy since 3 of the 4 enemies have "armor," meaning you can still damage them, but 1/2 the time it doesn't interupt their attacks. To make things worse, your opponent will either be buffed (extra damage or regeneration) or you'll be debuffed (lower damage or no blocking). The kicker is that if you beat one of the opponents while he/she is buffed (or you are debuffed), you'll gain about 15% of your health bar back.

The first of your opponents is Goro, and I hate this son of a bitch; mostly because he has armor on WAY too often. The trick to him is to stay mobile, his ground-based attacks have TONS of range. When he jumps forward to do a ground pound, jump AT him and kick him; you'll miss his attack and you can follow up with an uppercut. Alternately, he LOVES to jump at you, and rarely does his ranged attack, so if you have a ranged move that aims higher (Liu Kang's high fireball or Strykers low grenade, for example), you can consistently knock him flat on his ass.

Kintaro is next, and he's WAY too easy. You'll want to keep your distance to avoid his fire attacks, but when he jumps up into the air, quickly dodge and follow up. This is easy because when he misses his ground stomp move, you have a good 2 seconds to wail on him. This is where a good combo (I like Right + Y, Left + Y, then B, Down + Forward B with Stryker = about 20% damage) can really make a difference. If you don't know good combos, just consistently dodge his stomp (jumping works better than dashing IMO) and uppercut him.

Mileena is your third opponent, and probably the hardest. She doesn't have armor, but does consistently have damage increase (from my experience, anyway) and this will be where the AI hits you with an X-Ray. DONT let that happen. She loves to do the roll attack or teleport dropkick, so block a lot or do moves that keep you, well, on the move. Expect to lose a lot of health here if you aren't careful.

And lastly is the big motherfucker himself: Shao Kahn. You've probably fought him several times in the game, and he's no different here in terms of tactics: except one difference: YOUR ATTACKS ARE HYSTERICALLY WEAK (something like 33% weaker). Just keep your distance, and wail on him when he taunts you. One trick is try NOT to block, and instead crouch under his ranged attacks. This is because his hammer toss will stun you if you're blocking, but will completely miss if your ducking. Pounding him with constant ranged attacks (like Stryker's gun) does interupt all his attacks but the hammer toss, so be ready for that.

Other than all that, practice your combos and you should be fine. It's hard, but if you're good enough, you should be able to make it through.

UPDATE - Beat it. Shao Kahn is a bastard, but if you CONSTANTLY spam Stryker's gun (Left, Right, X) move, it's WAY too easy. Also, combine it with your RT move (X-Rays are borderline useless against him) and consistly use it. 8/10 times you'll interrupt his spear move, and the only move you have to worry about is the hammer toss.

Normally, you can duck under it, but it seems that he throws it a little lower in this instance, so JUMPING over it is the best choice. Not just because you can avoid it, but you get hit mid jump, you DONT get stunned.

UPDATE 2 - When I tried to do this again to capture it on film (which I did, see link), I noticed it was WAY harder than last time, in terms of damage caused, frequency of armor on enemies, and health gained. It took me a while to figure it out, but just like in classic Mortal Kombat, once the computer starts kicking your ass, eventually it tones down the challenge a smidgeon. I had to retry about 10 times or so for it to get to this stage of "ease."

"Best... Alternative... Ever!
Unlock Mileena's 3rd Alternative Costume.

This achievement requires you to pass OR skip the 300th challenge in challenge tower. You need 50,000 koins to skip, or you can beat the mission and you'll be rewarded with 10,000 koins, this achievement, and Tower Master achievement if you didn't skip any other missions.

*Note*
If you do skip missions, you can always replay the missions in order to get Tower Master.