It looks good. I always suggest people search on their target keyword and see the other thumbnails that come up in the search. Then ask - does my thumbnail stand out? Does it look like every other thumbnail in my niche? Would I choose it out of the list I'm presented with? Do others provide better information on the thumbnail?
I say this simply because when we have had other people in your niche post similar thumbnails, a quick search showed that the style you are using is very common to certain search phrases and may result in you having a great thumbnail, but it then gets lost because everyone's thumbnail is almost exactly the same.
We see this in the gaming niche a lot as well. Someone creates a great thumbnail, but then in the context of all of the other thumbnails, it is almost exactly the same and doesn't stand out.
I would recommend posting a much smaller version of the thumbnails for evaluation. Most people see your thumbnail on a mobile device (phone) screen and part of the trick is to make your thumbnail look good small.
These thumbnails above are nice and colorful!! (Great) But, I'm curious how readable your text is when viewed on a phone.