I would imagine a very low poly count for android. Android tablets and phones have a very small memory bank, usually allowing 250mb to 1gig of ram extra after the operating system is running depending on how much they have. I would significantly try to reduce that, or slice that into scenes that would be easier for that to manage. If you have too many verts on android, it would overheat it and essentially crash the program. I’ve had 3d games nearly fry my tablet from heat exhaustion. I would suggest no more than 10k polys per scene, ad I would really lower the amount of polys you have on your weapons as well. Android does not work with direct x. It works with open gl as well. I’m not really sure of the difference, but i’m pretty sure its how they draw renderings on screen. I would highly suggest to read up on android technology, and how the operating system works.
There might be a decent explanation on the os. You don’t necessarily need to read it, but knowing your way around how files and things are constructed might help alot when trying to work with sys commands, or creating files needed to save your character stats.