In MightThe Mighty Quest for Epic Loot, what determines your castle level and how much does it increase depending on upgrades?
You of course want to maximize the strength of creatures and traps in your castle without increasing your castle level, so knowing how it increases is important.
For example, I noticed that placing Roboshieldotron raised my castle level by 2, while removing it did nothing to lower my castle level. I've also noticed that certain research upgrades do not increase my castle level while others do.