WARNING: This port is very janky. Play at your own risk.

Changelog

Obtain a copy of Serious Sam: The First Encounter or Serious Sam: The Second Encounter and install it. Steam version will do.
Extract ssam_tfe_nx1.zip (for The First Encounter) or ssam_tse_nx1.zip (for The Second Encounter) into your /switch/ folder.
Copy everything from the game folder except the Bin folder into /switch/ssam_tfe/ or /switch/ssam_tse/. Do not overwrite anything if it asks.
Run the game from hbmenu.

The game takes a long time to load.
Performance is quite bad, especially on some levels, which seems to mostly be caused by dynamic lights.
The stock demos desync. I'm not sure if this is because this is technically version 1.10 and those are from 1.07, or because of something I did.
Because this is version 1.10 and most PC servers run 1.07, you can't connect to them. Not sure if I can just change the version number to 1.07, since that might cause desync if there are any significant differences.
Low framerate/broken timing in menus.
You can't control the NETRICSA menus (except for quitting them with the PLUS button).

This probably requires full RAM access, so don't run it from the Album.
If the game hangs at the first NETRICSA screen, that means it's still loading, wait a few seconds.
I have enabled the "Precache shadowmaps" option by default, which results in less lag in game, but significantly increases load times. If you don't want that, you can disable it in "Advanced options" -> "Rendering options".
You can turn dynamic lights off for a performance increase by setting shd_iAllowDynamic in Scripts/PersistentSymbols.ini to 0, but beware: dynamic lights are an integral part of some levels.
You can bring up the console by pressing MINUS. Press A to enter commands.
Play around with the Scripts/PersistentSymbols.ini file and Advanced rendering settings. I still haven't figured out the optimal configuration.
If the game crashes, take a look at the log file in the game folder (ssam_tfe/ssam_tfe.log or ssam_tse/ssam_tse.log).