Yep I agree with Indy. Bettas like hiding spots, seems the more the merrier. Also I cant tell if the large plant is live or fake (looks fake), but its always better to have live plants IMO. Some fake plants can actually damage your bettas fins (So I have read, I always use live so I have no personal experience)
You may find him flaring at the walls (his reflection) in which case you may need to figure out how to cut back on reflections. May also get stressed out from people being on all sides of him so you might want some backgrounds stuck to his tank.
The first paragraph I would address right away. The second is only if you notice its needed. Everything else looks good, sponge filter looks nice, all the chemicals and food in the background look like you are going to take care of him. Dark gravel is always awesome.