So, I've now finished it a second time, having played both branches trough to the end, now on my 5X. Still neat:-) Couple of minor points:
- If I turn of the device without exiting to the desktop the map is (at least often) blank when I return to the game. You can go on exploring and it will update the map with new walls but to get the old walls back I have to forcibly close the game. This issue seems to be new because I've only experienced it the last couple of hours of play but I can't know for sure if it's just something I never did earlier.
- When going up/down a set of stairs I often end up facing in strange direction, frequently towards the stairs. There are a few points where you're under attack from the very moment you descend and this makes those moment slightly panicky as you wildly try to turn towards where enemies might be.