Back up your own save files first!
1) They can be found at:
C:\Users\user_name\AppData\Local\Towers\Saved\SaveGames

2) Download my files from
Base game:https://drive.google.com/file/d/1uW1dXEfGMKpSgEZ86gARnD3GKPhb52rr/view?usp=share_link
DLC: https://drive.google.com/file/d/1nf7PMdckvvUfhmvEbv03Q4BI9UgOsu2y/view?usp=share_link

3) Disable Steam Cloud sync!

4) Replace the folder one at a time i.e. don't merge base game with dlc, (also make sure it's visible i.e. not set to hidden) and start the game.

Firstly, let me list what you can unlock from Base Game folder.

Home At Last
You've returned home after fully completing your mission! You're a hero!


Old Game Master
Assert your independence and beat Old Game Minus entirely in singleplayer.


The Answer is 42
Fully decrypt and watch the tower origin transmission.


Who Is Teratomo?
Collect and read every Alien Explorer Log.


Zoologist
Scan all the creatures on AR-Y 26!


Botanist
Scan all the flora on AR-Y 26!


The $600 Man
3D-print all the 3D-printables. After that, go ahead and 3D-print yourself a gold star!


Stronger, Faster, Probably Poisonous
Recklessly and irresponsibly eat every Orange Goo on AR-Y 26.


#################
Now, let's elaborate what's where.
Launch second save (Old Game Minus mode).
Travel to Pillars of Xzargana:


And proceed to that ashen dark island with magma pouring down:


There, scan baby bomb plant and yellow lizard:




Return to the portal and teleport to Festering Overhang

Press Z to get an idea where to drop down and jump below. The last orange goo is behind bushes between the pale carved stone (right) and double riding cables (left)


Continue to these mushrooms, solve the puzzle (melt amber rocks and move nuts to block acid vents)




Get to the nearest teleport and travel to Moist Vestibule

Again, press Z to locate alien log and sample, they're very close to each other:


After you have picked them up, jump all way down and return to your ship, where you have to watch/read through newly gathered intel:


Aaand unlock the last skill:

Right, so in DLC folder you can get these:
Power Underwhelming
Craft all the new upgrades unlocked via exploration of DL-C1


Coastal Postal
Collect all the scattered postcards of DL-C1


Jewel of the Bargain Bin
Complete the entire DL-C1 Kindex


#################
Now, let's elaborate what's where.
Launch second save (Old Game Minus mode).

While in the ship, get last upgrades:


Then travel to Boomerdale Beach:


Turn around, press Z and walk casually after the last card:


Then rush as lunatic along the beach and scan ginger dandelions:


Success?!

Download folder SaveGames (coop OGM & solo refueled) https://drive.google.com/file/d/1Zyh-b3xOjjsQBQ_6pYs_fpSHdaGZPBNK/view?usp=share_link

You can get speedrun trophy in either save file, in solo I'm under 2hrs and in coop OGM mode at 2hrs40mins.
No Refunds
Finish the game in under 4 hours. See you at GDQ!


Now, see these files?

Select save 1 to get this one:
Screw This Noise
You've returned home without fully completing your mission. I'd start looking for new work.


Select save 2 to get coop OGM
Old Game Alliance
Tolerate another person long enough to beat Old Game Minus entirely in coop.