Steam lists the game as having 60 achievements, but only ~38 actually show up in the achievement list to start with.
What "secret" achievements are there, and what are the requirements to unlock them?
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Steam lists the game as having 60 achievements, but only ~38 actually show up in the achievement list to start with.
What "secret" achievements are there, and what are the requirements to unlock them?
The update notes say:
Since they are along the same lines as the previous achievement, they mean the player should complete both the light world and the dark world of a chapter, and the sum of the best times for that chapter should be lower than some threshold. Here are the descriptions of each one:
About the old secret achievements:
petaphile
code to play with Tofu BoySources:
Note about the times for the achievements: Many people use Super Meat Boy Stats (old repo at Google Code, new repo at GitHub) program to find out how much time they have spent on each chapter. However, the reported total time is not exactly accurate because "it counts 15 secs per completed warp zone", and people posting their total times didn't mention if the warp zone time has been subtracted or not. For this reason, the times I posted above might be quite inaccurate.
Here is a compiled list of the hidden and some of the more cryptic achievements, from both personal experience, this list, and research (Googling, asking other ppl, etc). Let me know if any corrections are needed.
Some achievements might not pop up, so check for your profile to see if you obtained it.
Only the Booster 2.0 and the Iron Bond (by rescuing Curly) are required for the Best Ending (which you get after beating Ballos in the Sanctuary/Sacred Ground/Hell).
The 290 Counter (formerly the Nikumaru counter) is for the speedrun/time challenges (to unlock new tracks and characters on the title screen). The Whimsical Star helps a lot with the archers in B3 of the Sanctuary/Sacred Ground/Hell. Both of them are optional.
The Spur and Booster 2.0 is useful against Ballos' first 2 (and a half) forms.
"Happy Birthday Pixel" can be obtained by playing the game on April 29 or just set your computer date to April 29.
"Merry Holiday Happy Euphemism" is obtainable by playing the game during December 24 or 25th OR by setting your computer date to December 24th or 25th. You'll know you got it if all the sprites (and levels) are holiday themed - there's no popup for this achievement for some reason. See video.
"Ladies Man" can be obtained by sleeping with Chaco in Bushlands. All you really have to do is talk to her (check the fire at her house for the first time), and then sleep in the bed. You'll pick up the item when you wake up.
"Return the Favor" is somewhat tricky -- you have to unlock the secret dungeon by completing a series of tasks from Labyrinth onwards, then just get to a certain point in the dungeon (it's early on, in the first room, when you attach Curly).
"A Gift From Santa" is obtained by getting the Fireball, which is given by Santa of Grasstown as thanks for finding his key.
"A Fine Blade" is obtained by getting the Blade which you get after finishing the Sand Zone.
"Super, thanks for asking!" is obtained by getting the Super Missile Launcher, which is found in the Boulder Chamber after defeating Balrog.
"Arm Bar" is obtained by getting the Arms Barrier in the Labyrinth, behind a door in the high up passage above the physician.
"Turbocharged!" is obtained by getting the Turbocharger obtained from Chaba in the Labyrinth shop.
"Panty Raider" is obtained by finding Curly's panties. If you go to Curly's room there's a secret passage which leads you behind the wall and to the far right of the room. There you can find her panties.
"Tow Me A Rope" is obtained by getting the Tow Rope. Found in the Core's room (BEFORE the battle). The Tow Rope only appears if you did NOT get the Booster 0.8.
"Little Man" is obtained by finding Mr. Little. He is in the Mimiga Village Graveyard (he's green and extremely tiny, keep your eyes out).
"Home, Sweet Home" is obtained by taking Mr. Little home and talking to his wife (again). His home can be found below the Outer Wall.
"Ducking Awesome" is obtained by getting the Nemesis. After taking Mr. Little home, trade him your blade for the Nemesis.
"Freakin' Laser Beamz" is obtained by getting the Spur. Trade the Polar Star back to the Hermit Gunsmith (Use the Booster 2.0 to reach to the first cave and talk to him). If you collected the Machine Gun or the Snake, you won't get it in that game. If you got the Booster 0.8, instead of the 2.0, it becomes much harder to reach the cave to get the spur, but it can be done.
"Cold Hearted Snake" is obtained by getting the Snake. The shopkeeper in the Labyrinth Shop will combine your Polar Star and Fireball to create the Snake. If you collected the Machine Gun, you won't get the Snake in that game.
"I've Got Your Back" is obtained by getting the Iron Bond. This is obtained by returning Curly's memories by stuffing the mushroom in her mouth and then talking to her again.
"Count to 290" is obtained by getting the 290 Counter. If you have the Booster 2.0 and also saved Curly, you can get the 290 Counter from the chest in the clock room near the beginning of the Outer Wall. Otherwise, a mysterious force keeps the chest closed.
"Supa Star!" is obtained by getting the Whimsical Star. You get it from Chaba in the Labyrinth shop after you go back after obtaining the Spur.
(Some of the Boss related achievements might not work in Curly mode)
"Here's Johnny!" is obtained by getting the Alien Medal, which you get by defeating Ironhead without taking damage.
"Toroko Wins" is obtained by losing to Toroko w/o hurting her.
"Doggy Style" is obtained by beating Omega with one of Jenka's puppies.
"Only If You're Greedy..." is obtained by defeating the Twin Dragons.
"Swollen Mech" is obtained by defeating Heavy Press.
"Hate Made Flesh" is obtained by defeating Ballos.
"Cave Story Clone" is obtained by defeating G-Clone
"To Hell and Back" is obtained by completing the Blood Stained Sanctuary/Sacred Ground/Hell
"Who's the Boss?" is obtained by completing Boss Attack mode.
"Wind Fortress" Complete the Wind Fortress level in...
"Sanctuary" Complete the secret/optional Blood Stained Sanctuary level in...
"Boss Attack" Complete the Boss Attack mode in...
(Some of them might be bugged for some people)
"Mimiga Hero" is obtained by keeping the Mimiga Mask on (not getting the Booster back[...the final boss gauntlet xP]) and beating the game with it. I think it can be done on Easy.
"Coward" is obtained by flying away on the dragon with Kazuma in the Bad ending. (Blue Raja got it, but I was unable to :/)
"Unstoppable" is obtained by obtaining no life capsules and getting the Best ending.
"Untouchable" is obtained by obtaining no life capsules and getting the Good ending.
"Curse Broken" is obtained by getting the Best Ending. Clear the Blood Stained Sanctuary/Hell and beat Ballos.
"Shtuff Happens" is obtained by getting the Normal ending.
Best Answer
You can see the full list of Steam achievements at the steam site.
Out of the 60 achievements there are 20 that don't have a description. 10 of them are plot related achievements and you will unlock all of them (except from the Firestorm one) if you finish the original game:
UPDATE:
There are 10 more that don't have a description, 5 of them are related to the slingshot DLC, those are:
The other 5 do not appear on the xbox 360 version or the PS3 version, and have 0% completion, which means that nobody was able to get them, just as it was with the above 5 before the release of the slingshot DLC, those are:
As you can see, their description, taken from here, makes no sense regarding to the game. With the history regarding the slingshot DLC they are probably related to a future DLC.