There is no official Black Mesa Android APK , as the game was developed by Crowbar Collective

The infamous "Blast Pit" and "Xen" chapters still see minor frame drops due to complex transparency effects.

: Often struggle with the Source Engine's lighting effects, frequently requiring "lite" asset packs or significant setting reductions.

Advice on which service works best for Half-Life games.

This is a grey area. While the Black Mesa mod itself is free and legal on PC (requiring no original Half-Life files), the often bundle modified engine code and assets from the original Half-Life. Distributing the valve folder is illegal. However, downloading only the texture pack and launcher while using your own Half-Life files from Steam is generally considered acceptable under fair use for personal, non-commercial purposes.

Do not ask for or share pre-packaged APKs that include the valve folder. Instead, follow the steps above using your legally owned copy.