There is no way to go back to the title menu in-game outside of either dying or restarting the app. Once you click Play in the title menu, you are also unable to go back to title menu. I'd suggest adding "title menu" to the game menu and make Escape open that menu in most scenes.
The analytics agreement however, is shown every. single. time. Please save the selection.
It'd be cool to keep seeing default card types. For that matter, it'd be cool if the Shop rewards were weighted by respective deck percentages, or randomized, or based on current transformation, and for basic attack/shield to be obtainable (these have ? value). Also, normal cards are mostly weaker versions of other types, but there is no incentive to pick them. ie story, unlocks, achievements, special bonus? I mean, you don't even stay male with 100% default type.
The statuses on enemies is sometimes easy to miss, particularly with taller enemies and thorns blending into certain models. You should put it directly under the health bar, where the eyes are already looking to calculate hp/dmg.
Drag and Drop could be a bit bigger to make using cards on enemies easier. There is also a defense/utility card that requires you to drag to yourself (when other such cards don't).
Offensive cards should be able to drop anywhere (like block cards) if there is only 1 enemy.
Opening your deck, or clicking too fast, can cause the Shopto duplicated remaining options, allowing for 2 uses of each. This may be an endless shop issue specifically, calling the previous shop version by mistake.