1. Start with Mercury Stone in the menu / left to "Opera backstage" / do it / learn climbing, jumping, shimming / climb ladder / before learning crowling, jump to metal bridge for flares + 1 LMP + 1 SMP over the lower metal tower / 1st pool, underwater tunnel, 2nd pool / vertical underwater pit, pull up in room with 2 ammo, 1 LMP / hrope room (hrope can be ignored): at the groundlevel enter next depot / climb [action] shelves: flares / pull left empty rack: ammo / pull right empty rack: room with Truth Mouth, uzi clips, climb shelves (action) to get Secret #1 out of 3 / after hrope: another room with a Truth Mouth and shelves to climb: 1 SMP / switch to exit to streets.
2. Ahead and right, kill a dog coming from Fountain Square / flares on the tent of Antico Caffé Recco (jump from the fountain) / action at Truth Mouth #1, clearing way to Truth Mouth #2 [bats! tip: sprint away] / back to Mouth #2, climb a new block / climb a ledge with columns / RJ to get a SMP nearby / back to ledge with columns.
3. Stairs / get the terrace level, chairs, short bridge to other house, safety drop / shoot windows 3x (SMP, ammo, nothing but the possibility to jump to next house: wait) / down to courtyard / dog / pull door to open / another dog / a barrel room: 1 LMP, ammo on the crate / out to couryard / switch to open gate to Fountain Square (don't exit) / back to broken window #3 / jump now to next house / junction: right to nothing (roof), left to Gold Key / back to dogs' couryard to get Fountain Square / random dog near the gate where the Gold Key should be used.
4. Use the Gold Key / save the game: Larson ambush / tip: sprint left under Larson's fire, up stairs, fire him while sidejumping / back to the courtyard for 1 SMP / down to basement for Garden Key #1 / up where you shooted Larson / hrope / safety drop / switch to exit (don't exit) / left / blue ammo / a locked wooden gate you cannot open now/ / pan camera / get the revolver / pull door / laser sight at left / wooden locked gate at right / fire the lock by regular pistols while crowling, or use revolver with laser sight / save the game / enter, rats! / roll and sprint away to open air (don't need to fire) / back to get Garden Key #2.
5. Use both Garden Keys / enter the Garden / MOVIE: stone #1 (Mercury) out of 4 fixed on portal / forget the pool for now / follow the tunnel from the Garden up to the bell building / running jump to get the red roof where Larson and the other guy where / another RJ to ammo and 1 LMP / back to the bell building / another laser sight under the bell / combine revolver and laser / fire once the bell / get the regular pistols, you'll need them soon / find a hole on the left wall / RJ to a Truth Mouth, bats! Tip: trigger the bats, roll and jump to the bell building area, shoot them here / get the Mouth again / action to Mouth opens the upper tunnel.
6. Left, switch to transmute left bird / turn its column / right, up the new stairs (opened when rotating the column) / crowl under the pendulum, append, shimmy all right, pull up / switch to transmute right bird / safety drop / turn second column (right one) / exit to bell building area / enter the lower tunnel / don't get Saturn symbol now (= end level): you still have two more secrets to get!
7. Two more secrets to get: back to the "locked wooden gate you cannot open" of 4, actually t's open since you shooted the bell / dog inside / climb right shelves to get Secret #2 out of 3 / nothing from the other shelves (or a SMP, I don't remember) / back to the bell building / RJ to Truth Mouth again / "magic" alcoves (don't know the exact moment they are open) with 1 SMP and Secret #3 out of 3.
8. Enter the lower tunnel again / get Saturn symbol now / exit: end level / MOVIE: stone #2 (Saturn) out of 4 fixed on portal / Important Lara speech: put the remaining 2 symbols on the gate quickly, before that... Boom! [this will be clear at the end of next level]