You can peer into the interior a little bit around the edge of the door, but other than that, there is no seeing the interior layour of the tower. Looks quite intact.

To the immediate right of the D shaped corner tower there are the low remains of what I'm pretty sure was a postern gate protected by an Iron yet. Immediately on passing through the gate, there was a stairway leading...somewhere. You can tell that it was probably a yett by the circular hole where one of the securing pins would have gone into the stonework. Many yetts had two, each secured by large padlocks. One would have been fairly high and the other fairly low.

Here are some shorts of it.

It's hard to tell what the functions of all these buildings once were. There does appear to have been a small D shaped tower at the SE corner.

The tower house itself had it's own projecting stairwell tower, which is largely intact. It had a length of courtyard wall built against it as well as a range of buildings, which can be seen in stonework which doesn't get much above foundations, as well as a inverted v roofline along the stair tower.

I keep coming back to that high entrance on the main tower house though and the rough jagged stonework going up to it, along with a roof slant mark. Seems like a pretty substantial structure went very high up on the front facing side of the castle. Probably some sort of guard room linked to standing watch over the gate below. That would be my best guess. It sort of gets in the way of the big window, though, so the big window came later.

The ruined corner tower was pretty impressive in it's own right, with high quality dressed stonework over a rubble core. There was a range of buildings connected to it inside the courtyard.

You do have a bit of the remnants of the one corner turret here, but only a hint of the one above and to the left of the gate structure.