What are the notable differences between desktop and mobile play?

[Ungod]

I want to know the limitations.

[Aia del Mana]

The limitations of mobile play are largely dependent on the method used to access MagicDuel on the mobile device, and the specifications and capabilities of the device itself.

Those with a mobile device with significant hardware limitations may want to use the older mobile link - http://www.magicduel.com/mobile 
This particular interface will allow one to read and respond to the Chat in the scene one is currently placed in, check and reply to in-game messages, check the latest updates, check the mood-panel and create a mood-status, and logout. Other features are largely unavailable with this specific method, but performance is very fast compared to other mobile methods.

Those with a more powerful mobile device will likely be able to access most game features. Currently, development is in progress to make interface interactions easier for mobile users.

Some mobile devices will have the capability to use "Desktop Mode", which may further decrease the interface limitations, but may also drain the device's battery faster.

[Miq]

You will be in disadvantage in most activities while being on mobile.