Spend light to reveal the next actionable hazard, preserve a pulse for recovery, and invest coins in the upgrade blocking your current climb.
5 Seconds of Light is about spending visibility, not memorizing an entire dark tower. A floor is shown briefly, then torch pulses and drafted perks reveal or protect the next part of the climb. Spend light on the obstacle you must act on and preserve a recovery option for the hazard after it.
The App Store lists two modes: Levels, with coins, permanent torch upgrades, and checkpoints; and Speed Run, with five fixed towers and Game Center leaderboards. It also names 15 perks, including light tools and survival options. Exact upgrade prices and perk values are not stated here because the current version is still changing.
Use the 5 Seconds of Light torch guide to decide whether the current failure is a visibility, survival, or restart-distance problem. That diagnosis is more useful than buying every upgrade evenly.
The current listing supports iPhone and iPad and says there are no forced ads during a level. Monetization and upgrade balance can still change, so check the live version notes.
Sources
QUICK ANSWERS
Questions players ask next
What are the two modes in 5 Seconds of Light?
Levels is the continuing climb with coins, checkpoints, and permanent torch upgrades; Speed Run uses five fixed towers with Game Center leaderboards.
Are upgrades bought with real money?
The developer says climb upgrades are earned through play; the only money purchase described is removing ads.