ah, sorry about that. The version of the game you're playing is outdated.
The map got a complete overhaul and redesign. And the letter pieces could be collected .
As for this area, the steps to get out of here is to press your down and jump button and dash away from the spikes.
Next you need to find the three eye monsters in the area and kill them to get rid of the giant gate blocking your way at the start of Twilight Grove, the area you're in right now.
Next all you need to do is head West, then Northwest respectively. You can explore the other surrounding areas though.
As for the recent update on the game, it's currently available on Steam with all the issues fixed.
Sorry for the inconvenience. 😅
Also, here is a picture of a portion of the map for the demo so far, hopefully it helps.