What to collect

Temporal Shards

25 in every main stage, 200 in the whole game. The common collectible. Some sit on the route, some are a jump off it, and some want an ability you do not have yet.

The HUD counts them for the stage you are in. The campaign total is on the results screen and in Extras.

Time Lord Relics

3 per stage, 5 in the final stage, 29 in total. The rare one. Every relic is somewhere that takes real work: behind a gate, at the top of a climb that is not on the way to anywhere, or past a hazard you would sensibly avoid.

They count towards your completion percentage and your rank. They do not unlock the Extras menu - finishing the story does that.

Secret rooms

At least 3 per stage, 35 in total. Walking into one counts it, so stumbling in sideways still gives you credit. Several need an ability from a later stage, which means a stage you have finished is still worth revisiting.

Permanent upgrades

Temporal Heart raises your maximum health, for good. One in each main stage and one in the final stage, so nine in total.

Vortex Cell raises your maximum energy, for good. One in each main stage, eight in total.

Both are permanent across the whole save. Taking one refills the bar it raises.

Easter eggs

Thirteen of them, hidden in wall text, in scenery and in one or two places you would not think to stand. Found ones are listed in Extras; the rest show as blanks.

Achievements

Thirty, all local. Nothing is uploaded anywhere. Some are for beating each boss, some are for collecting, and a few are for things you would only do by accident or out of curiosity.

Secret achievements show as ??? until you earn them, so the list does not spoil the back half of the game.

Completion

The completion percentage is weighted rather than a flat count:

It reaches exactly 100 only when everything is taken. It is shown on the results screen after every stage and in Extras.