Some feedback:
oc_longways
add a func_clip_vphysics brush to first combine barrier as the blue barrel can be accidentally dropped over the top.
Consider using waypoints or just use lighting sprites or whatever imagination to highlight where some of the objectives are.
After I killed the gunships, I had to noclip past the barrier where cameras areas I couldn't figure it out.
(The way you move to each section of the map is a bit of a mystery).
Change the toppled building hanging over wall. Get rid of the random pieces of wooden barriers at spawn and a model of some sort for cover.
Map seems very tough with respawning enemies consider making it easier and adding lives or something. Add a modify_txt with spawn items, weapons at spawn is very hl2dm like.
oc_inlight
This map just needs a lighting and texture overhaul, A small puzzle map like this needs to look better for the player to want to hang around and finish the map.
Also the room with the moving walls is badly built there's a gap where I can see back into the kitchen.
oc_systems2
Again this map is a bit confusing concering objectives and where they are.
Lighting issues in the spawn room are a bit of a put off, some of the walls you can see the texture unless you use a flash light, it shouldnt be this way.
Some scrren shots of what I mean.
Now some advice tips.
Bear in mind everybodies map could be improved in one way or another and I don't think your really taking the time to look at your own work and think how can this be improved. I really think you need to spend more time on each project and make the effort to fix and make changes, strive to improve more.
I think you need to focus on just about all aspects of making a map.
Architecture
lighting
ambience
texturing (more realsim) and watch how you scale some of your textures sometime high scale texture next to a low scale texture can look awful.
gameplay
orientation
features Use more of obsidian's feature to give your map the right feel for coop. (stuff like a map_briefing.txt, using spawn items, using info_waypoints, taking advantage of modify_txt's add spawn items) Just make your maps less hl2dm.
I think you can learn alot from playing your maps and some of the official oc maps and see how the above features from oc can be used in your maps.
I wouldn't be saying all of this if your maps were just fun maps that had a focus on gameplay over graphics.
But I think you spent some time and enjoy making your maps look good, but they all feel a little half finished.
So far I've only got frustrated and noclipped though most of the maps.
(Though I was quick testing). I think you'd get more interest in the map both play time and feedback from players if the maps were of a higher quality.
Your halfway there, I'm pleased you make maps for oc and though my feedback isn't very positive, you have some nice ideas, your mapping skills aren't the worst. Just try to really polish your work so it shines and stands out from the rest.
I'm no expert I'm not 100% happy with any of the work I've done, though most of my work I've attempted to improve. None of them are as perfect as I like.
I know its easy to jump from one thing to the other, but try to push out maps that are much more finished.
lastly I feel that your maps are two small or short.
You have the potential, its up to you to do better. I wish you luck.