Vine

Vines hang in the Jungle's rooms, whose room script makes a vine from each tile that would be a Ladder in the Mines', and in the Black Market. To the code a vine is a kind of ladder, so everything about climbing one is the same, but its top: a ladder's top is a rung to stand on, and a vine's isn't. Monkeys start out on them.

The player climbs a vine exactly as he does a ladder: up in front of it, standing or in the air, takes hold, up and down climb it at 1 pixel a step, and the jump key throws him off ^{[1] [2]}. A fall doesn't count while he climbs ^[3]. The clip shows it in the Jungle's green rock: the player climbs a vine hanging past a ledge, jumps off toward the ledge at its top, catches its edge and pulls himself up.

A vine's top is a kind of ladder, not of ladder top, so it's climbed like the rest of the vine and isn't a platform: nothing stands on it ^[4]. How a vine looks is set when the level is built: its top block is drawn as the vine's source and its bottom block as its end ^[5].

The Sun Room has vines the room editor placed ^[7]. In custom levels they're the level editor's tiles v (a vine) and t (a vine top) ^[8].

• Monkeys. Level generation puts a Monkey on each block of vine with a 1 in 15 chance ^[9]. It climbs up and down its vine, turning where the vine ends, and leaps off at a player below it ^[10].
• Bombs don't destroy vines, which aren't solid, as they don't destroy ladders ^[11].

• A vine is safe to climb down however long it is, as a ladder is: a fall doesn't count while the player climbs.
• With no top to stand on, a vine that ends below a ledge is left by jumping off toward the ledge, as the clip does.