Developing for Tablet Only Coding

I am developing a touch screen kiosk, it will be used exclusively on tablet devices (Samsung Galaxy Tabs).

I've developed the application like I would any normal web application, using HTML5 and CSS3. It's fully responsive and adapts to different screen sizes.

The interface is very simple, offering a few large buttons (href links) that when clicked on open a modal window. Nothing fancy at all.

I've noticed some 'lag' when tapping the buttons on a tablet as opposed to clicking in a browser. I can't figure out if this is a hardware of software issue. I've ensured that all the buttons are large enough and allow for any 'fat finger' issues.

I haven't used any JS Touch Events, I didn't think it would be necessary?

My question is, should have coded the application any differently seeing as it will be used exclusively on tablets? Or is using standard HTML5 and CSS3 acceptable?

Any advice is appreciated.