Thanks for the feedback! It is actually set to 1080x1920. I will definitely use a smaller resolution, I have a vertical monitor and didn't realise this was an issue
The second point I've already fix it :) it but didn't make it in time for the demo build. It now has a larger area so it is easier to aim to enemies, and it also shows a dotted line to make it clear where you are aiming.
Also, I have in mind to add a small tutorial to teach how to use every card type and introduce them slowly in the levels, once again, didn't have enough time...