Press F2 in Pizza Tower to become any transformation or swap between Peppino and The Noise, right in the level.
Transformation Picker adds a menu to Pizza Tower: press F2 in any level and pick any transformation the game has, or swap characters without going back to the main menu.
When the menu opens, the screen goes dark and your character freezes in place, but the music and sounds keep playing. Everything is written in the game's own font.
Controls
The list
Pepper Pizza is the R-R-Freezerator power. As The Noise, it's the jetpack from that level.
Single player. You need your own copy of Pizza Tower on Steam. The mod builds a modded copy from your install and patches your own game files on your PC, so your Steam install stays untouched and your saves are shared. It rebuilds itself whenever Pizza Tower updates.
Credits: Transformation Picker by The Gnose. Pizza Tower by Tour De Pizza. Patching is done with UndertaleModTool by the Underminers team (GPLv3).