Thanks for your review!
I think it was meant to be like that because you took the paid door at the previous level. At the end of each level, you can choose between two doors:
- The opened door and the next level will be normal
- The closed one which costs you golds and will disable some hazards
So I think you took the closed door because those spikes are meant to be broken when you take that door. The sprite isn't clear enough but it's something we will work on after the rating period is over.