I want to create a small arcade game that can be played on steam. I was also wondering if it is possible to port a game you made for pc into a mobile app? Thanks, as you can see I’m a newb any response is appreciated.
Ummm… Unity? 
Yup possible.
Yes, I’ve done it repeatedly, but it becomes exponentially harder the more intricute your controls and GUI are. 
No problem 
If it’s a cross-platform game project, using Unity will save you quite a bit of time.
If only there was a popular cross platform game development tool that’s both free and accessible
Well Unity fit in this category I think 
And if only that tool had a forum where users could discuss the tool…
Well, a big issue is just how much of the “arcade” experience you want to emulate. If you are shooting to have your game available on Steam, than probably not that much.
While “arcade” has become shorthand for simple, short-term games that focus on action, the actual definition is very much tied into how those games were sold. The idea of dropping a quarter into a machine to play a game was central to the design of those games. Everything about original arcade games was informed by that pricing structure. In order to make a proper “arcade” game, you have to build the title around that payment model.
I would have originally said that Unity was not the engine to use for arcade games. But when they released the Linux port of the run-time engine, that opened things up considerably. If you design an arcade cabinet, using a commercial OS like Windows or OSX is very cost-prohibitive. Those OS are also not optimized for just running a single program. Being able to run Unity games on Linux greatly expands the usefulness of the engine in creating full-on arcade games.
For your specific purposes, yes, Unity is a fine option.
Thanks a lot guys