Press 0 (zero) to toggle invulnerability.
Dungeonfield is a sandbox-style RPG action adventure game that might feel a bit familiar if you've ever played Terraria. Plunked into a 2D, side-scrolling world randomly generated and populated with dangerous dungeons, and you'll need to smash, stab, dig, and otherwise destroy your environment to gather the supplies you'll need to craft and survive day-to-day. Turns out in a great battle, the kingdom was destroyed and all its people carted off to dungeons, and only you can save them. Right after you replant these tulips. And chase that kitty. And build a giant stone sign saying BUTTLORD and wait until your husband notices because that's how you show you care.
You can generate any size world you want, and choose to play to rescue and rebuild, or simply enjoy creative mode. If you've never played a game like this, you might want to run through the tutorial to learn the basics first. You move with [WASD], use  and  to cycle between available items, and click on most things to interact by hitting them. If the object, anything from the ground to trees and more, can be destroyed, you can pick up the remains by walking over it and using them as ingredients to craft other helpful items. Though you start out with just the basics, as you explore and find new materials, you can make a wide variety of items, from simple decorations to bling out the fortress I'm sure you plan on building, to tunnels you can link up to travel instantly anywhere in your newly generated world. Die? Don't worry. You'll just respawn at your last save/load point.