Tower Level 5 Quests

Main Quest: Engineers' Retreat
To reactivate the teleporter the party must investigate a nearby "ancient battlefield". Up the stairs in a corner is a blue light, marking the item which grants access to the engineers retreat.

Side Quest: Expedition documents
Find all the notes.

Side Quest: Faradus
To complete his quest the player must interact with the power generator by the fountain slightly north of this position and the dispensing machine, which can be found heading east from Faradus.

Main Quest: Mechanical construct
Interact with the 3 levers in this area to reactivate the energy pylons. The Construct can be powered up once the pylons active and all connected with each other. The next step is to upgrade the Mech (damaged robot back in the Rusty Library, to your right as you entered the floor) and exploit its ability to open locked doors on this floor. The default code for the old typing device is 1-1-1-1, which can be read on the note on the left of the Heavy Steel Door.

Side Quest: Mystery of numbers
Find all 12 codes for the Dispensing machine. The codes offer rewards.
 * Troubles: 0112
 * Great Magic Incantation: 0409
 * Armageddon's Blade: 1008
 * Old Scroll: 2129
 * Expedition Breastplate: 2268
 * Expedition Boots: 4756
 * Expedition Helmet: 8832
 * 4 Edicts: 4444
 * Purple Crystal Stock: 7703
 * Secret of Tower Avatar: 8084
 * Mana Diffuser: 9011
 * Magic Incantation: 9993

''Secret Code for Bonus Battle: 0666 (there is no ingame notes or hints for this code) Starts a battle vs multiplicating deaths. It doesn't seem you can win this fight. You cannot withdraw after entering the code. (Another user: You CAN win, it's reward 4000 gold and 2hand powerful hammer)(Another user: Easier to win if you return after completing a few more floors.)(Yet another user on epic: 4800 gold, could win by walling off with Kane + cannons. Earth curse + fury will also work.. somehow easier than 1st battle on 6th floor with portals)''

I had a problem here that I could only get the most recent code out of the Dispenser, so be careful with saves to prevent losing out on the critical part - Mana Diffuser.

Main Quest: Power generator
Four pieces are machinery are required to fix the generator. Note that only 3 of them are laying around spread across the level, while one must be retrieved from the dispenser through a code input.

Reward: Access to the lower floors of this level.

Puzzle: Platforms & Switches
The easiest way to solve this puzzle should be by activating the switches in the sequence as shown in the labelled screenshot on the right.

Notes:

Platform 1 has just a single switch, it must be activated in the beggining to pass to the next platform, and a second time when the other puzzle steps have been completed, unlocking the passage to the Secret Platform 8.

Platform 5 has an additional switch unlocking a shortcut to backtrack.

Platform 6 also has a code to unlock an optional secret platform on the east side. (code 0515)

Side Quest: Geometry shapes and codes
The Titan Boss can be made stronger by enabling the codes/icons or weaker by disabling them.
 * Square: 1024
 * Circle: 3141
 * Triangle: 0180

Alignment - Body Search
When searching the bodies, you can choose to search the bodies, or pay respect to the fallen.
 * Search the bodies: 300 gold, Maeve +1, Aeric -1, Boron -1, Whisper +1.
 * Pay respect to the fallen: Maeve -1, Aeric +1, Boron +1, Whisper -1

Alignment - Robot Decision
When exiting the level, you can choose between keeping the robot in your party, or removing it's power core and gaining an amulet


 * Keep with party: Robot assistant, Kane +1, Aeric -1, Rakhem +2, Boron +1, Whisper -1, Kaela -1 (unknown how assistant plays out, I did not continue with that option). (Another user: He continues with you for a floor, then stays behind while you go on.)
 * Remove power core: Kaela's Amulet, Aeric +1, Rakhem -2, Boron -1, Whisper +1, Kaela +2