The Tunnel Man is a friendly NPC whom the Spelunker meets in the tunnels between areas, where he asks for "a little money" - several hundred thousand dollars - so that he can dig a shortcut.
These shortcuts give you the option to bypass previous areas during future playthroughs, skipping straight to the later levels.
Unlike virtually everything else in Spelunky, the amount you've paid the Tunnel Man remains constant even after you die, so you don't have to pay him all in one go.
After the first shortcut has been dug, he can be found sitting in the shortcut house between games.
You encounter The Tunnel Man in tunnels between areas (at the end of levels 4, 8 and 12), offering to dig shortcuts to the start of the Jungle, the Ice Caves, and the Temple respectively.
The Tunnel to the Jungles costs $100,000, the Tunnel to the Ice Caves costs $200,000, and the tunnel to The Temple costs $300,000.
He won't appear the first time you reach a new area, but he will appear the second time and will remain there until you pay him all the money he needs to dig a shortcut to that level.
The Tunnel Man will not appear in a later tunnel if the preceding shortcut hasn't been dug yet, and he only appears once per run - even if the funding for the preceding shortcut has been completed on that run and the player has reached the next shortcut tunnel before.
To pay the Tunnel Man, press up and down to change the amount of money you're offering him, then press the action key to pay him.
Obviously, this removes the money from your inventory, so you may not want to make a donation for the shortcut if you anticipate getting a high score.
As a Playable Character
The Tunnel Man becomes a playable character once the player unlocks all 4 Challenge rooms and at least one shortcut. He can be selected by going to the shortcut house and entering the door on the far left.
His abilities are much the same as the Spelunker, but there are a few significant differences:
- Instead of a whip, he uses an unbreakable mattock as his default attack. This allows him to smash through walls effortlessly, but makes it impossible to attack while in the air.
- He starts with only 2 HP and no bombs or ropes, but can still gain HP from damsels and collect equipment from crates and shops.
- When revived with the ankh, his HP is reset to 4.
If the Tunnel Man is unlocked before all three shortcuts have been dug and selected as player character, an NPC Tunnel Man will still appear in the corridors between areas asking for donations, making this the only instance in which a character can meet themselves.