Tutorial says "Jump on enemies to kill them" I think " Oh man it's going Mario style now" jumps than brings out his sword and slashes the guy on the head I think "Oh that's how you kill them..."
Should have, in similarity to not being able to do quests before a battle not being able to select the travel option for training, just to make it more realistic.
A kind of annoying yet cool thing is that there are two paths for upgrades starting when you start upgrading and unlike kingdom rush not at the last upgrade and it gives the game a lot of different kinds of towers from just one root tower, another thing which is nice is you can put your towers anywhere on the map, well mostly.