A small update, and almost all of it came from your reports on the forum. Thank you helix2, Zatoichi and garwilm.
Professions
Your profession is applied properly again. Starting a new campaign after finishing one could leave you stuck with the profession from your previous run, without ever being asked to choose. You now always get the choice.
The Merchant and the Elementalist described themselves wrong. Their cards promised starting towers that didn't match what you actually got. The towers were always right — the descriptions weren't. Both now match the game.
Fixes
Burning enemies stop burning. A fire effect could linger on an enemy long after the flames were out.
The map can no longer disappear, leaving only sky. The camera could be moved past the edge of the battlefield, most easily on Silent Necropolis. It now stays over the map on every level.
Performance
Late waves run smoother. Big Endless waves are lighter on your machine than they were.
This performance work is a first pass. If the framerate still drops for you as the enemies pile up, please keep telling us on the forum — that's exactly how this update happened.