A couple of questions

[Awesome Kalin]

Each question is on a new line
Would I be able to run a graphical app?
Would I be able to write an OS for this?

[Kylogias]

1. Graphical app? Probably, it is turing complete
2. Yes (I'm already planning on writing DOOM and a C-like compiler for it)

EDIT :: While these are technically possible, it's highly unlikely under 32KB of ROM

[jdh]

Yes and yes, as @Kylogias says it's Turing complete and it has support for arbitrary devices.