SECRET IN COLOSSEUM
TRLE Level by Benji
Walkthrough by Treeble
We begin by sliding down into a pit with a locked gate. Check the rocky slopes on the right to spot a wall switch, there's a flat surface you can climb on to reach it. The switch opens the gate, indeed, but before heading there jump and grab the flat opening in the wall, next to the slope through which you arrived, to claim SECRET #1 (approach the slope from inside for it to trigger): a large medipack and flares.
Through the gate, pull out the obvious block from the wall and move it aside so you can enter a corridor that was hidden behind it. This is technically secret #2, but it's incorrectly coded, so just take the explosive bolts and the GOLDEN ROSE as a memento and then hop over the lava gaps to a jump switch in the end of the side passage. Another gate opens in the main hallway, so go back there.
Grab the crevice on the wall and shimmy all the way over the chasm. When you drop on the other end, pull up into a crawlspace and drop inside to find the next wall switch. Crawl back out and jump over the chasm to the open gate where an eager lion awaits. Drag the dead body in the corner for a small medipack before jumping into the water pit.
Emerge on the other end and kill three lions, then proceed to throw that skeleton lever in the corner. The trapdoors above you drop open, so climb the ladder and backflip at the top. Collect the REVOLVER and the STAR KEY from the pedestals.
Run through the doorway next to the ladder to stumble upon a viking (I think?). Gun him down, then head up the small slope to face another viking. There are two alcoves on the left side of the room, get a small medipack from the short one before dropping into the water pit in the other. Swim towards the other end and take the SILVER KEY, plus UZIS and SHOTGUN, from the pedestals while a skeleton whacks at you. Leave it behind as you swim back to unlock that gate in the corner.
At the end of the slope, jump to a flat surface. Line up a running jump to grab the leftmost edge of the rocks ahead. Go right and climb up to the top of the area to collect a couple of goodies from the pedestals: another STAR KEY and a large medipack. Retrace your steps down and now follow the opposite path. Just as you reach the leftmost end of the collapsed path, you'll surely notice an alcove in the wall. Jump in for would-be secret #3, another GOLDEN ROSE, explosive bolts and shotgun shells.
Hop over the lower blocks attached to the supporting columns of the central structure and jump all the way to the skeleton lever in the back. A timer shows up on screen, so don't dilly-dally and jump all the way back to the top of the room to find the exit gate is now open. Quickly run in.
Drop through the hole in the corner for a slope. When changing from one slope to the other, you could jump and veer off to the left to a small landing where you could find a large medipack and shotgun shells, but I wouldn't bother. Resume your descent and proceed to slot in both star keys next to the closed gate.
Slide down another slope and, while the centurion statue screams and throws bolts at you, jump over the railing to the right to find a large medipack and the CROSSBOW. You can kill the creature if you so desire, but apparently its only vulnerable when both of its arms are down (so if it's pointing the sword at you or walking, all of your efforts are in vain). It might be smarter to just take the ROMAN HELMET from the pedestal and escape through the open gate, leaving the guardian behind.