The stages

Nine of them, in one order. The stage select draws the route rather than a list, so you can see at a glance what is done, what is next and what is shut.

How they unlock

01 ─ 02 ─ 03 ─ 04 ─ 05 ─ 06 ─ 07 ─ 08 ─ FIN

Finishing a stage opens the next one. That is all of it. There is no point in the campaign where you have to work out which way to go.

Anything already open stays open, and you can go back into a finished stage whenever you like. That is where the optional half of the game lives: the shards, relics, secret rooms and permanent upgrades that a later ability opens. Nothing on the way through a stage is ever locked behind something you do not have yet, so you can always finish a stage the first time you reach it.

The stages themselves

1. THE DERELICT OF SKARO. A dead station above a burned world. Teaches you to move. Ends with something that has been patrolling deck four for nine hundred years and is still certain it is winning.

2. STEEL ASCENSION. A conversion ship, still running. The stage climbs because the ship is a vertical factory. Timed platforms over a drop with no floor under it.

3. WAR OF SONTAR. A battlefield. Almost every room gives you something to stand behind, and almost every enemy can shoot through the gap if you stand in the wrong place.

4. RED ICE. Mars, under the surface. Long gaps, tight caverns, and stopping is harder than starting.

5. THE FALSE EARTH. A suburb built by someone working from a description rather than a memory. The houses repeat. Some of the walls are lying.

6. SHADOW LIBRARY. A library the size of a planet with the lights failing. Light is a resource here, and the dark bites.

7. SILENCE. A concrete facility nobody remembers building. The rooms repeat almost exactly, and the thing in the corridor is only there while you are looking at it.

8. THE MASTER'S CLOCK. The inside of a mechanism the size of a cathedral. Nearly every platform is on a timer, and they all share the same four beats as the music.

9. THE END OF TIME. Reality coming apart, with pieces of all eight stages floating in it. Every room quotes a room you have already survived. Three fights, no shards, since there is nothing left to collect, but five relics.

What each stage holds

Every main stage: 25 temporal shards, 3 relics, at least 3 secret rooms, one Temporal Heart, one Vortex Cell, and three checkpoints - two in Stage 1, which is the short one. The last checkpoint is always in the room immediately before the boss.

The final stage: no shards, five relics, one extra Temporal Heart, and a checkpoint between each of its three fights.

Revisiting

Finished stages stay open. Since several gates want abilities from later stages, going back with a full kit is how the last relics and secret rooms get found.