1 through 4 - In the landing area behind some crates.
5 and 6 - In the second large hall, fuel up on the jetpack pad than fly to a walkway above the area. Follow the tunnels until you get two tribals.
The exit in that area leads to the Water Ruin.
7 and 8 - In the lava room with criss-crossing platforms, jump down and go into a drainage pipe. Follow the walkways in the next room to get the
Tribals.
9 and 10 - In the first room past the lava room. Use the jetpack to get to them.
11 - In the next room. Use the jetpack to get to it.
12 - In the 3rd room after the lava room. Fall down onto the platform with the Tribal.
13 through 15 - In the room where there's the green key and a jetpack pad, shoot the too glass windows in the ceiling. Use the jetpack to hover from
platform to platform, than fall back down and exit the level.