Impressive for a first game! This reminds me of 007 goldeneye on the N64. I agree with the other suggestions, and have a few extra that might help:
- The player can move faster diagonally then they can going either straight or sideways. This can be fixed by normalizing the player's movement input, then multiplying it by your desired speed.
- The jump feels a little floaty, personally I would tweak the values for this a bit to make the fall happen a pinch faster than the rise of the jump
- The player can't jump if they are on top of certain objects. The player can jump if they are on the floor or the railing, but they cannot jump if they are on crates or walls.
Again, certainly impressive for a first game! I enjoyed playing this game, nice job!