I watched several people play this game since I unfortunately cannot due to lack of computer. First time was with Cry, then Pewdie, though I watched all the possible endings.

WARNING DO NOT READ IF YOU HAVE NOT PLAYED/WATCHED THE GAME. SPOILERS ALE

At first, I was pissed off at Mary for killing Garry, but after some thought, I understood her point. But I also understand Garry's.

Marry pro-
*She's 9 and she sorta acts like it, even if she is a painting.
*She's been in the messed up world for her entire existence, so yeah it's understandable that she wants to see the outside world.
*She was lonely, and when she saw a chance to get out, she did what she could. Most people would.
*She behaved up till the point Garry found out, he became distrustful and she knew it, so she reacted violently. Fighting for her life basically.
*She liked Ib, Garry was more of the threat and she wanted a sister.

Marry con-
-She did throw her own 9 year old tantrum, which is expected... But she kinda took it in a psychotic way. Evil laughter, stabbing doll heads, and going on a killing tantrum.
-She doesn't feel any remorse by killing Garry.
-Basically hunted you through the whole Crayon world.
-She is a painting, and a figment of imagination. She doesn't have a true family that could be sacrificed if Garry or Ib stayed. Though not much is known of Garry. Plus, she doesn't have to eat I'm sure, while its possible that Garry and Ib could starve in that world.
-SHE CREEPY DX

Garry pro-
*He honestly is a nice guy, a nice lady talking nice guy.
*He is mostly your, and probably Ib's, emotional support through the game.
*Comic relief, he says silly things and that's takes talent since.. Ya know, everything is trying to kill you.
*He seems to really care about Ib. His main focus through the game seems to be helping Ib get out more than his own. He proves this by bothering her to put the naughty book down, explaining things she doesn't know like the milk puzzle, giving comforting words, instantly thinks of Ib's safety when he discovers who Mary is, and does the biggest sacrifice by giving Mary his rosé for Ib's. Not even giving Ib a choice on the matter. He then doesn't want to lie to Ib that he is okay, but he doesn't want to say that he is dying. He didn't want to freak her out by himself freaking out. He is one brave man in my opinion going through all that.
*He is a real person, so he probably has a family to go back to. Maybe a girlfriend, we don't know.
*He offers candy and to take Ib to try some macaroons... That's awesome

Garry Cons-
-Again, we don't know much about him other than he seems pretty nice, cute, and he talks like a lady.
-He doesn't hesitate to mistrust Mary once he finds out. He instantly steers him and Ib away from her. Although I understand where he's coming from, things might of been different if he had been more understanding towards Mary.
-He's a bit of a scaredy cat, but I don't really blame him. I'm sure I'd freak if I had bunches of fan paintings after me.

Ib Pro-
*Shes also a real person. She has a mom and dad back home.
*Shes only 9, so is it really fair to leave her in such a demented world? I ponder if they would stay there, they would eventually just starve to death since they are real.

Ib Con-
-We don't really know her personality. According to Garry, she seems like a tough girl, but the whole situation does take their toll on her. She apparently misses her parents when she sees their painting. She might just be quiet but I suppose it's up to ones imagination since your playing as Ib.

So who really deserves to escape? I think it's a no win situation. Although I lean more for Ib and Garry since Mary went psycho, I do feel for her. I would of liked a option if you sacrificed yourself. So I shall add two extra scenes that don't really happen, but would be nice.

Save Ib and Garry?
Save Ib and Mary?
Save Gary and Mary?
Save Ib and Gary but leave Mary alive in the painted world?
Save just Ib and screw them both? XD