Mobile 2.5D MMO Game Development Advice

I’m reaching out to my fellow developers to get some advice and guidance on making a mobile game such as Game of War, Mobile Strike, or even Vikings. I have been doing a lot of homework googling but seems the mobile game development community is pretty tight-lipped on their trade secrets.

I have broken it down to different pieces I need to research: - Inner City – orthographic (2.5D) city builder. Not sure if this is a true tile map layout or not. Assets don’t seem to exactly line up like they should. Need to keep user inventory via a database via a Web API. Chat service via photon or similar service.

Game Map – a massive undertaking. Seems to be a 2.5D tile map with hundreds of players. Players need to be able to calibrate in battles, gather resources etc. From what I have read a lot of this can be handled by a photon server or similar service.

I know this is a huge undertaking but I am up for the challenge. Baby steps right?

Been a business app developer for over 20 years but always have wanted to get into game development. Not sure if my development experience is hurting or helping me. Definitely a different style of development. Old habits are hard to break. lol

Anyway, not looking for nothing but guidance. I’m willing and able to do my homework. Thanks in advance.