Hey, Grats Killer! Does this mean you'll be coming back to us again now that you've got villains outta your system?
heh Gratz! PL Meh!
Haven't seen a screenshot of the dev dungeon in ages lol
MA Arcs - #67636, #92202
deviantart page
Slag Heap: Why you hurt Guardian!? Guardian no hurt you!
Where is this hidden dev dungeon?
"Timid men prefer the calm of despotism to the tempestuous sea of liberty."
"Nothing is unchangeable but the inherent and unalienable rights of man."
- Thomas Jefferson
The dev dungeon is a hidden room that's off the tunnels that are below Grandville, there's a map of the tunnel way system on the Printout map of Grandville at vidiotmaps.com Along the tunnels there will occasionally be place the usual Arachnos type technology, mostly near corners the entrance to the dev dungeon is hidden by one of these clumps so you kinda have to walk into and behind them to get to the entrance, similar to the entrance to the break room where the Easter Egg exploration badge in Faultline is hidden.
MA Arcs - #67636, #92202
deviantart page
Slag Heap: Why you hurt Guardian!? Guardian no hurt you!
Grats indeed 
Here's a screenshot of my Merc/Dark Mastermind hitting lvl 50 on Triumph. I went to the hidden Dev Dungeon in Grandville and had a friend teleport me inside the cage.
Enjoy!
Killer-X- (lvl 50 Justice)
Killer Knight (lvl 50 Triumph Villains)
etc, etc...
Killer Knight LVL 50