Bizarre shader bug with portal 1

Earlier than I clarify the problem:

My cellphone is a Google pixel 9 professional xl operating android 16.

Now, I put in (or tried to) portal 1 utilizing the supply engine port discovered within the discord for nillerusr port of supply for android, and I needed to play portal 1 on my cellphone, so I downloaded the engine from the information, and put in what I assumed I wanted, copied over the portal recordsdata from steam on my PC into my android cellphone inside storage > srceng excluding the bin folder, and ran the sport, the primary menu appears to be like superb, however then I am going into the primary chamber and it appears to be like like this (screenshot offered)

Any and all assistance on this matter will likely be drastically appreciated.