Glad to hear you enjoyed it, your comment made my day! The title wasn't meant to be a reference to Time Crisis, but in hindsight thats a much cleverer idea XD. I just couldn't come up with a consistent theme or idea of this game while developing it.
I don't really like doing level design, but I concidered doing a level design jam with some of my friends to make more levels for this game. I'm not sure we will ever get around to doing that though. I really enjoyed programming the boss, I would love to be able to make more of them at some point.
A sliding mechanic would be good, and would add to the parkour/platforming experiance I think. If I was gonna add more content, I would probably also add more weapons and add grenades and health items.
Yeah the audio and UI could probably use some work. Theres lots of settings in unitys audio system and I don't really know how I'm supposed to be using things like spread. The idle dialog/response system was something I implemented pretty last second, if were to do it again, I would probably make it so asking a question is on global timer so they wont overlap. I could also make some soft global queue for the combat vocal barks to stop them talking over each other. UI is another one of my weaknesses, I'm not really sure how I would make it look good, so I tend to focus on polishing up the gameplay and mechanics instead.
I would love to make and release a longer FPS game at some point in the future, because these are great fun to make. It probably wont be this exact game, but I imagine it would have a lot of the same mechanics!