Looks damned sturdy!
I'm guessing you are somewhat limited in your woodworking experience and tools. Having said that, it looks fine. Certainly better than I've ever made. I did a small woodworking project as an x-mas gift and know how hard the simplest thing can be for someone lacking skills.
I don't know how much of a challenge doors would be, but they would hide all of your equipment/supplies.
55gal - Coralife 4x65w cf, xp3, flourite, Hydor ETH300w, pressurized CO2 w/ rex(TM) reactor!
30gal - 55W AH, ecco 2232, flourite/gravel, DIY CO2 w/ Hagen ladder
3gal - endlers/cherry shrimp
4W cf, Red Sea deco nano, flourite