How to Reach 100 KM in Drill to Earth's Core — Run Plan

What a 100 KM run actually is

100 KM is not a new mode. It is the same descent, taken far enough that you pass the 100,000 m mark and hit a Glowing Core Boss Wall — the special wall that appears in the Heart of the Earth layer at every 100 km.

That changes the shape of the run. A short descent is a resource loop: mine, fuel, upgrade, break a wall. A 100 KM run is an endurance check where three specific points decide whether you make it. Everything else is preparation.

The full depth and HP table is on the layers page; this page is the plan built on top of it.

The three failure points

1. The Void Clay Wall Boss at 17,000 m

The Clay Layer’s boss wall is completely covered by Void, and arriving at it empties your drill’s fuel. This is the most common way a healthy run dies, and it has nothing to do with combat skill.

The fix is preparation: carry 3 to 7 coal or more and charge the drill early rather than arriving on fumes. If you are running Mechanic, your fuel contribution bonus makes this noticeably cheaper for the whole team.

2. The Toxic Layer boss wall at 41,000 m — 25,000 HP

Boss wall HP steps up sharply here: 10,000 HP at the Crystal Layer, then 25,000 HP, then 50,000 HP one layer later. This is where under-invested drill power stops being a nuisance and starts being a run-ender.

Two things help. First, the rest stop on this layer has been broken and swallowed, so if you intended to sell items here, push to the next rest stop instead — or stop and collect coal. Second, the shop here sells a guaranteed Gold Medkit, which is the one reliable heal in that stretch.

3. Wolf Bat at the Glowing Core wall

Wolf Bat appears when you drill the Glowing Core Boss Wall. Its pattern:

• It teleports between four positions.
• It charges an energy orb that grows from big to giant, then explodes.
• After throwing the orb it rushes the players to attack.
• At 0 HP it is stunned and fully regenerates its health in 10 seconds.

That last line is the whole fight. You are not going to kill Wolf Bat in the usual sense — you are going to survive its cycles long enough for the drill to finish. Bring 1 to 2 Golden Medkits or a Revive Kit, because a wipe here costs the entire descent’s progress.

The upgrade plan that makes it possible

Drill power is the only stat that meaningfully shortens a 100 KM run, and three upgrades do almost all of the work:

The combo is the point. RPM Overclock ramps Ultra Drill’s stacking damage faster, and Power Burst multiplies whatever has accumulated. Used on a boss wall in that order, they are worth more than any three combat upgrades you could buy instead.

Full costs, rarity odds and the rest of the upgrade list are on the drill upgrades page.

A practical run order

1. Before you leave the lobby — check your class. Driller for drill power, Mechanic for fuel, Reaper or Tank if your team keeps wiping in rooms. The tier list explains the trade-offs.
2. 0 – 10,000 m — this stretch is soft. No Little Walls at the very start, and the first dungeon sits at 1,000 m. Use it to bank ore and buy your first upgrades.
3. 10,000 m onward — mutations begin. Keep buying drill power at every shop, and remember that Little and Large Walls appear every 700 m to 1 km, so Coin Walls or Monster Engine upgrades turn that frequency into income.
4. 17,000 m — pre-load coal before the Void Clay Wall Boss.
5. 41,000 – 61,000 m — the HP steps are brutal here (25,000 → 50,000). If your drill is behind, this is where you find out.
6. 84,000 m onward — Void, Toxic and Fire mutations can all roll together. Wall HP peaks: 500 HP Little Walls, 5,000 HP Large Walls, 500,000 HP boss walls.
7. 100,000 m — Glowing Core Boss Wall. Revive in hand, drill through, survive Wolf Bat.

After the run

Career total depth is what gates Level 4 team bonuses on every class, and a 100 km clear adds 100,000 m toward those gates. Reaper’s team bonus, for example, gates at 10,000,000 m — so a 100 KM run is one small step on a long road.

If you are short on the Cores you wanted before attempting this, the Cores guide covers the fastest sources. If you are brand new, start with the beginner guide instead — a 100 KM run assumes you already have a class and a few upgrades behind you.