Played the demo v2. Good work so far on it. Just a few c&c for you:
1. Video has a few spelling mistakes.
2. Having multiple doors in an area such as you did- may I suggest that it might be good to widen the hallway(s) where these are. Gives the hud for the door a chance to fade out as you approach the one opposite, if that makes sense. Also gives room to manoeuver around the doors. If I did that, I might consider having the hallway 2 squares wide with the doors on both sides. This way if I approach a door and see "Press Enter to Use", I won't miss the hud for the opposite door telling me I need a key.
3. Couple of glitches on the outside where rock faces were touching. I get that too on a couple of my levels and generally ignore it. Every game has something like that appearing.
4. I would also suggest it may be good to have a trigger to show Objectives when you first start. Another idea is to have a hud that can be displayed and when the O key is pressed, the objectives show. Gives the player a chance to refresh his/her memory on what they need to do in the level. If the objective is to neutralize all enemies, then that's the objective. If we need to find a key to open the door to access level two, then that is the objective.
5. I agree with making the ceiling a level higher. Feels kind of "boxed-in".
Overall, a good start on it. I will certainly watch the progress on this game and look forward to seeing more.