I passed all levels but didn`t found it. Can someone give me a hint where to seach it?

I finished the game and bought bunch of helmets but didnt get achievement so I started a new save and played until I got money for the cheapest and still didnt unlock the achievement

No exit in sight, or switches. Collected all stars and pressed E everywhere... nothing.

https://steamcommunity.com/sharedfiles/filedetails/?id=2862062260 There's a huge upward arrow, but it's too high to jump on. Some hints please? Thank you very much.

MacOS : - The main menu when loading into the game for MacOS runs at very low FPS, after loading a level it is fine. Working on fix benched for v1.0.3. MacOS & Windows : - On certain levels, if there is more than one moving enemy, when killing one of them, the rest of them become invincible. - Customization Achievement may not trigger, fix available here - Moving enemies on certain levels are invincible due to...