Thank you a lot for your comment! You made clear some important points that need further improvement/polishing. We really didn't think opening doors like you mentioned, maybe that way will make the game feel more different and rewarding.
We have some variety of enemies, but they have all the same properties. Maybe they are a little hard when you first start, unfortunately we didn't have much time to playtest it .
Recoil jumps are difficult to master yes... but once you get it, I believe it's pretty easy to replicate. Maybe a little tutorial room with all of those techniques will make things easier to practice and understand.
I'm a little sad to tell you this but... no, there's not a red gun :`(. Let me explain: there are 2-way doors and 1-way door, you can travel a 1-way door only from one side., the other side(red door) is unlocked once you travel from the other side. Maybe if we had a map were you can see the entire level would make things easier to understand.
Finally, thank you so much for your feedback, really appreciate people like you how play the game till the very end (and more in your case lol). I think your comment will helps us when we do the Post-Mortem.