The general rule is that you may not reach Level 10 except by killing a monster. 1 of any Munchkin base game for more information. See the "Conflicts Between Cards and Rules" box on p. However, there are certain rules that must be specifically contradicted by cards. In general, rules on specific cards override the general game rules. Most of the cards in Munchkin have rule effects of one type or another. We added one important question about unequipped Steeds, Vehicles, or Ships (short version: you can't) and a few others that don't quite rise to that level of universality. May 2019 update: We've cleaned up a fair number of things throughout the document. We've also made the answer to the "owner of the game" question more explicit. Churninator (from Munchkin Cthulhu): Add "unless this would give you the winning level" at the end of the first sentence.
If you can't find your answer here, check the errata, to make sure we didn't make a mistake. Frequently Asked Questions for all Munchkin Games, Supplements, and Accessories Updated April 20, 2020