If you want to find these by yourself, here are the number of hidden doors I found, so you know when to stop looking for more.
I don't count doors opened by switches or by enemies. The exceptions are the recharge station on Research, and the 2 connected doors in Executive.

Medical: 7 One is on the floor.
Research: 2
Reactor: 4. 2 of these are connected.
Maintenance: 1, once maintenance doors open.
Storage: 2
Flight Deck: 1, you'll need to find it for 0% level security.
Executive: 3. 2 of these are connected.
Alpha Grove: 1
Beta Grove: 0
Delta Grove: 0
Engineering: 1
Security: 0
Bridge: 0

Contains: 2 medipatches



Contains: 1 frag grenade


Contains: 1 Reflex, 1 Illudium-Cadmium Battery, 1 EMP Grenade, 1 Minipistol, 2 corpses


Contains: 2 crates (I got 1 frag grenade)





Contains: Bio systems monitor V1, Medipatch, 3 crates (I got a proximity mine)

Requires 0% level security

Contains: Magnum 2100 pistol, 1 corpse (I got magnum bullets), 3 EMP Grenades

To open: crouch jump on the small ledge to the right, press the button inside


Contains: 1 Proximity Mine, 1 EMP Grenade

Contains: 1 Logic Probe



Door above and below are connected





Contains: 1 First Aid Kit, 1 Magnesium-tip box

Contains: 3 Illudium-Cadmium Batteries

To open: Use the button on the wall behind the desk

Door above and below are connected


Switch inside unlocks it. After using it, you can open it from this side.


In Alpha Grove

(After maintenance is needed and using the retinal scanner)


Contains: 1 Gas Grenade, 2 EMP Grenades, 1 Proximity Mine

Contains: 1 Logic Probe, Osmium-core rounds