it may just be me, but I wasn't able to open the picture.

Bright colors with lots of contrast are very good for developing eye coordination. Helping babies to focus etcetera. Primary colors are always good. Maybe paint the walls a cheerful yellow with bright red curtains and blue Linens Etc. I do know one young mother who painted her baby's room white with all black accessories. Her logic was that that was the highest contrast a person can get LOL.

I would hang the decal on his door (back or front). Kids love photos of themselves and photos of their family. So at the foot of his bed I would hang a print (could even be a canvas wrap) of him with his family in the largest size you can afford. EDIT: make sure you hang it low, so he can see it easily! Or you could do a collage frame with shots of various extended family members. My little guy loves pointing out the people he knows in photos (he'll be three in March) and it helps little ones feel a connection with family who is far away that they might not see often, if that is a situation you can relate to. Other than that, a low pile rug that he can drive cars and build with blocks on and you're finished! It's a perfect room for a little one to grow up in: just enough room to play and small enough to tidy easily, a neutral wall colour to let his imagination do the work, a big mirror for dress-up days and making faces and generally admiring himself. Good job! Oh, and about the window, go with the code spacing for railings when determining the safety (I think it's 4"). If he can back his body out and his head gets trapped, oh no.

I would use a pillow like this and add some of the tones to the room. https://www.zazzle.com/vintage_fighter_airplane_colorful_accent_pillow-256148911545180493?rf=238772772155923633&tc=8b405bc794df186109cc05991229c69c&utm_source=bing&utm_medium=cpc&utm_campaign=us_shopping&utm_term=PRODUCT_GROUP&ca_chid=2001810&ca_ace={aceid}&ca_nw=o&ca_dev=c&ca_pl=&ca_pos=&ca_cid=&ca_agid=1201766632238043&ca_caid=352493965&ca_adid=&ca_kwt=&ca_mt=e&ca_fid=&ca_tid=pla-4578710040758167&ca_lp=&ca_li=&ca_devm=&ca_plt=&msclkid=8b405bc794df186109cc05991229c69c