1: Starting off
2: Working upwards
3: Later levels: Sentinel has friends!
4: Sentinel's Stare.
5: A starting position in difficult terrain
6: A 'map view' of a landscape
7: A view to the top
8: Zoom, zoom, zoom
9: Spectacular mountain landscape
10: Scanning: well-hidden?
11: Tougher levels, more Sentries!
12: No energy, scan imminent! Must transfer!
13: Hard terrain. Keep your options open
14: The Sentinel sees you from afar
15: Moving to hide
16: Get out of that one...
17: Map View shows it's safe for now.
18: Sometimes close moves are best.