Is it possible to solo a tier 3 level if there is at least one out-of-reach (like, completely) gun puppy (rocket launcher, you know, those that don't miss in tier 3 and have 2nd rocket flying your way by the time you dodge 1st), which spawns when you enter a maze-like level (zig-zag corridors with no walls so shots by one gun puppy can fly over the whole area freely)?
If rocket puppies spawned as I progress through the level, or area had walls, or there were other limitations on monsters, it would be possible to solo that level. But currently I see no way around it - its impossible to solo... unless you're Chuck Norris >:D
For the record: I came in full VOG set (maxed heat), with grey owlite shield (maxed heat). There is no problem with damage - everything dies in 2 hits. There is problem with monsters doing very high damage to me, with their projectiles chasing me around the level at speed I can't dodge (second rocket is already flying by the time 1st one explodes).
Level in question:
Golden falcon gate, Clockwork tunnels - mechanized mile at depth 19.
The clockwork tunnels levels are randomly generated, so whether you get that particular segment or not is completely up to chance.
That said, you'll probably find that bringing a polaris with you will make such situations much, much easier. You should be able to get off a couple shots before having to shield the first rocket hit, and then if you time things right the puppy will be interrupted long enough to be able to keep spamming it until it dies.
Another option is to use an RSS to pick off the puppy from outside its aggro range.