Tecnically its minor nitpicks, I wont go into.
From the visual standpoint, its a color soup.
Social media are underlines with green, First product shot is reddish-pink, Background is blue and reddish orange, and the radioactivity logo is yellow with a pretty ugly green glow.
The tagline "Tritium Light Keychains – Magic in your pocket." is a) hard to read, bcause its red on reddish orange Background b) Cheesy as hell c) not actually in the theme of radioactivity
"Safe, reliable, useful." is better and you shouldnt have more then 1 tagline in the first place.
(Although from my personal POV, the light seems pretty weak and not useful at all, also the radioactivity thing would make me think twice, before id just take that led keychain thingy)
But enough of that, back to the actual review:
The footer is stretched beyond the content of the actual blog and looks misplaced
Change "Welcome to the home of “TritiumKeychain.com”." to "Welcome to the website of TritiumKeychain.", sound better IMO.
"These make excellent presents for the guy or gal who has everything and likes unique, one-of-a-kind or high tech gadgets. The coolness factor is high in these keychains!" Is just cheesy.
Move the Buy now button up, so ppl dont have to search for it. The images are black on white Background, which looks ugly. Stick to the white BG product shots like on the start of your werbsite.
The BG image (the atom bomb) does not play well with the rest of the site, keep it more simple, Also on monitors greater than 1080p, the bg image cuts off. Either fade it away or remove it.
I can't give you a "besides that its ok", it needs a lot of work. Also "and the theme is heavily modified by me" is just nonsense in the context of a forum with webdevs lurking around. Keep it honest.
Rework what you actually want as a theme. The radioactive or the dark style look? Dont mix'em together.
Since "Recent Comments" and "Categories" are empty and basicly useless, since all the interaction with customers will happen on social media, remove them.
Also, the social media links are broken. Thats a big big no no.
Lastly, that multicolored strip on the very 10 pixels of the website is just useless and should be removed.