Thanks for playing our game !
Adding an indicator to show where you jump would be a good idea ! We might add it if we decide to polish the game a bit.
For momentum I agree it's hard to keep it, but it is possible. Momentum is killed if your jump is in a direction opposite your momentum. Otherwise wall-jumping would be impossible (you'd crash into the second wall). The problem might be that opposite here means at an angle >90°, so it's pretty unforgiving. Perhaps with a bit more leeway (say 100 or 110°) it'd be easier.