The design looks crisp and smooth, very modern and very sleek.
I prefer the red colour since it feels more warm and inviting whereas a colour such as blue may feel cold.
The UI is pretty nice and appealing to look at, some of the colour schemes are decent too. I’d maybe make it a bit more rounded and add a drop shadow to the frame, but other than that, great!
My favourite colour scheme is probably the purple one.
I love how it’s so simple and easy to understand. If I had to pick a favorite I would probably say the purple one, but the color really depends on the type of game.