On the Subject of Completion Marks

...Isaac? What happened to you?

This module begins by displaying Isaac in his default state before he descends into the darkness of the basement below. Along his journey, Isaac collects a set of 4–7 pickups—each one altering his appearance with a unique visual effect. The number on the button always reflects the total number of pickups Isaac currently holds. You must evaluate Isaac’s loadout and determine which boss(es) he is capable of defeating. Once identified, you will check off the corresponding completion marks on Isaac’s personal note. Repeatedly pressing the numbered button will cycle through three views: Isaac, Isaac with pickups, and Isaac’s personal note. Additionally, the module includes + and – controls that allow you to zoom in and out on Isaac’s modified appearance for closer inspection.

The types of features a pickup can modify are:

• Total Body
• Minor Body
• Mouth
• Left Eye
• Right Eye
• Both Eyes
• Forehead
• Side of the Head
• Head Accessory

There are some notable restrictions on pickup type combinations that can help determine Isaac’s pickups:

• There cannot be more than one pickup of the same type.
• A left eye pickup will always be paired with a right eye pickup.
• Both eyes pickups are exclusive to both left and right eye pickups.
• A forehead pickup will always be paired with a side of the head pickup.
• Head accessory pickups are exclusive to both forehead and side of the head pickups.
• Certain pickups may have multiple effects on Isaac’s appearance in the Appendix, but only one effect can be visible on Isaac’s character. (i.e. Maw of the Void can affect Isaac’s total body, mouth, and both eyes, but only one of these changes will be visible on Isaac’s character as seen below)

Maw of the Void	Total Body	Mouth	Both Eyes

Use the Appendix to locate Isaac’s pickups. After determining the names of all pickups Isaac has, go through the following list from top to bottom unless told otherwise:

1. If there is a BOB indicator, and Isaac has Bob’s Curse, then he can beat every boss in the game with ease. Immediately check off every completion mark in the personal note in any order.
2. If Isaac has Eye of Greed, Head of the Keeper, Pay to Play, or Dad’s Lost Coin, and there are 2 or more indicators, then Isaac is actually in greed mode and can beat Ultra Greedier. Proceed immediately to Completion Mark Submission.
3. Otherwise, proceed to Completion Mark Calculation.

Completion Mark Calculation

1. Take each pickup name and remove any non-letter/non-number characters, including spaces.
2. Count the total number of characters in all of these pickup strings, modulo that number by 20, and add 1 to the result. Call this number X.
3. Take the the Xth character in each pickup string, wrapping back to the beginning of the string if X exceeds the length of the string.
4. If an obtained character is a letter, convert it to a number using A1-Z26, then sum the values of all numbers. Modulo the sum by 26 and add 1 to the result. This number is Isaac’s power.
5. Input Isaac’s power into the table below to determine the final boss he can defeat, resolve lines 6 and 7 below, then proceed to Completion Mark Submission.
6. **If Isaac has exactly 4 pickups, and there are exactly 4 batteries, then Isaac can beat the Boss Rush.
7. ***If the serial number contains a character in common with SILENC3, and the final boss is NOT The Beast or Mother, then Isaac can beat Hush.

Power	1-2	3-5	6-8	9-11	12-14	15-17	18-20	21-23	24-26
Boss	The Beast	It Lives!	Isaac	Satan	Mother	???	The Lamb	Mega Satan	Delirium

Completion Mark Submission

Using the final boss obtained previously, mark the corresponding symbol(s) in reading order into Isaac’s personal note.
*If Isaac’s power is even, mark in place of ---. Otherwise, mark in place of ---.
**If Isaac can beat Boss Rush, mark before any other symbol.
***If Isaac can beat Hush, mark after .

Boss	The Beast	It Lives!	Isaac	Satan	Mother
Order
Boss	???	The Lamb	Mega Satan *	Delirium *	Ultra Greedier
Order			---	---

Filled and unfilled personal notes are visible below.

Appendix

Use the Appendix to identify the pickups Isaac has. Each entry will have the name of the pickup, what type of effect it may have on Isaac’s appearance, and an image of the overall effect. Effect types are labeled as follows:

• B. = Total Body
• A. = Minor Body
• M. = Mouth
• L. = Left Eye
• R. = Right Eye
• E. = Both Eyes
• F. = Forehead
• S. = Side of the Head
• H. = Head Accessory

NOTE: Some combinations of pickups are very difficult to identify due to overlapping colors/positions. While most combinations should not encounter this issue, the defuser can still select the green D4 to reroll Isaac’s pickups. However, the D4 needs 3 charges in order to activate it. Charges are built by solving other modules and are visible next to the D4.

2Spooky B. M. E.	Mars B. M.	Anti-Gravity B. F.	Neptunus B. M. E.	Dead Dove B.
Spirit of the Night B. M. E.	Libra B.	Abaddon B. E.	Maw of the Void B. M. E.	Bob’s Curse B. L.
Jupiter B. E.	Transcendence B.	Terra B.	Box A.	Tarot Cloth A.

Midas’ Touch A.	PJs A.	Akeldama A.	Shard of Glass A.	Aquarius A.
C Section A.	Bucket of Lard A.	Cancer A.	Compound Fracture A.	Blanket A.
Match Book A.	Spirit Shackles A.	Dirty Mind A.	Crack Jacks A.	Death’s List A.
Mom’s Purse A.	Gnawed Leaf A.	Mr. Dolly A.	Camo Undies A.	Mom’s Key A.
Consolation Prize A.	Empty Vessel A.	Soul Locket A.	Stop Watch A.	Revelation A. E.

Ball of Tar E.	Eden’s Blessing E.	Trisagion E. F.	Contract from Below E.	Holy Light E.
Glaucoma E.	Sacred Heart E.	Rubber Cement E.	Proptosis E.	Uranus E.
Judas’ Shadow E.	Haemolacria E.	Pop! E.	Stigmata E.	Squeezy E.
8 Inch Nails E.	4.5 Volt E.	Ipecac M. E.	Common Cold M. E.	Scorpio E.
Knockout Drops M. E.	Roid Rage M. E.	Dark Matter E.	False PHD M. E.	Sulfuric Acid E.

Speed Ball M. E.	Cricket’s Head M. E.	Cricket’s Body E.	Epiphora E.	Dad’s Lost Coin E.
Torn Photo E.	Mom’s Eyeshadow E.	Bozo M. E. S.	Tropicamide E.	Continuum E.
Mucormycosis E.	Lachryphagy E.	Fruit Cake E.	Pyromaniac M. E.	Sausage M. E.
Chaos M. E.	God’s Flesh E.	Eve’s Mascara E.	Rotten Tomato M. E.	Venus E. H.
Tooth Picks E.	Technology Zero E.	Pay to Play E.	Head of the Keeper E.	Eye of Greed R.

Chemical Peel R.	Bird’s Eye R.	The Peeper R.	Blood Clot R.	Mom’s Eye R.
Ocular Rift R.	Stapler R.	Guppy’s Eye R.	Mom’s Perfume R.	Lost Contact R.
Dr. Fetus R. H.	Tough Love M. R.	The Wiz R. H.	Technology R.	Technology 2 L.
Anemic L.	Dead Eye L.	Mom’s Contact L.	Stye L.	Cursed Eye L.
Glass Eye L.	Lead Pencil L.	SMB Super Fan L.	Almond Milk M. L.	Soy Milk M.

Red Stew M.	Placenta M.	Apple! M.	Blood Bag M.	Mom’s Lipstick M.
Playdough Cookie M.	Serpent’s Kiss M.	Sinus Infection M.	Dead Onion M.	Dead Tooth M.
Dog Tooth M.	Charm of the Vampire M. F.	Ghost Pepper M.	It Hurts M.	Jesus Juice M.
Binky M.	PHD M.	Monstro’s Lung M.	Whore of Babylon M. F.	Mutant Spider M. F.
Godhead F.	Inner Eye F.	Polyphemus E. F.*	Evil Eye F.	Cracked Orb F.

*Polyphemus counts as a Forehead pickup and Both Eyes pickup at the same time to comply with combination restrictions.

Eye of Belial F.	Tech.5 F.	Skeleton Key F.	My Reflection F.	BFFS! F.
There’s Options F.	Options? F.	More Options F.	Marked F.	Zodiac F.
The Mark F.	Luna F.	Eucharist F.	Starter Deck F.	Large Zit F.
Cat-O-Nine-Tails F.	Lump of Coal F.	Wooden Spoon F.	E.Coli F.	Bomber Boy F.

Black Candle F.	Curse of the Tower F.	The Parasite F.	Virgo F.	Little Horn F.
Tiny Planet F.	Lodestone F.	Flat Stone F.	Small Rock S.	Pentagram S.
The Battery S.	Jumper Cables S.	Marrow S.	Lord of the Pit S.	Mercurius S.
9 Volt S.	120 Volt S.	Dead Bird S.	Wire Coat Hanger S.	Voodoo Head S.
Steven S.	Spider Baby S.	Purity S.	Black Lotus S.	Pageant Boy S.

Sharp Plug S.	Boom! S.	Battery Pack S.	Magic Scab S.	Skatole H.
Card Reader H.	Goat Head H.	Mom’s Wig H.	Spelunker Hat H.	Magic 8 Ball H.
Magneto H.	Strange Attractor H.	Cupid’s Arrow H.	Bloody Lust H.	Broken Modem H.
Metal Plate H.	Super Bandage H.	Brimstone E. S.	Blood of the Martyr H	Halo H