First of all let me say that this is a really early impression I would like to share, maybe getting some feedback or tips in return.
My observations might be based on the fact that I did not quite wrap my head around the ins and outs of timelines yet, or I might be spoiled by more advanced software that has been around for a lot longer than Construct.
That being said:
At first I was puzzled by the key frame selection tool. I'm used to being able to select keys by default in most track views and it always worked well for me. Using the selection and moving some frames to a new position I'm missing visual feedback. It would be nice to see the frames markers move with the mouse like in any other software I've used, instead of just the marker with two lables for absolute and relative offset.
To me arranging keys and finding the right timing is a visual process, where I need to see how the keys align with other keys. Especially when things get more complex this is quite essential imho.
Another nice feature I miss are selection ranges. When animating it happens a lot that you are happy with a rhythm you created, but the object animates too slow compared to other objects in the same timeline. Being able to select all keys and drag the ends of that selection range to scale the selected keys in time would be great.
When in edit mode I would expect to be able to select multiple objects, modify them and set keyframes for all of them.
Instead only one of two objects gets keyed and the other jumps back into place so I loose my edit. Why do I have to select and key the objects one by one?
The zoom options are nice but apparently I can't zoom out any more than 1x, which shows 18 seconds of animation, probably OK for many applications, but why not make the zoom more flexible. My favorite solution for this is using the mouse wheel plus Ctrl or Alt to zoom in and out.
Maybe that's me being used to more modern 3D Software interfaces like 3DS Max or Maya or engines like Unity, and I don't know about the technicalities behind the interface, but in my experience animation editors can be more intuitive and when they are they are even more powerful tools :)
I had to work with Flash professionally for a couple of years and eventually got the hang of using the timelines there, but to me they felt outdated even at the time. So I would be really happy if this aspect of Construct would evolve towards a more visual and more intuitive interface like Unity has...