Adjective for something that increases in difficulty

I'm creating a game and in the name I want to include an adjective that shows something that increases in difficulty. The problem is that I don't have that great of a vocabulary and the internet didn't seem to help. I don't even think there is such a word that can explain that. If there is no such word than I would appreciate it if you gave me words that have a similar meaning to what I am asking for.

I'm creating a game and in the name I want to include an adjective that shows something that increases in difficulty.

That's called escalating.

Escalating (adj): becoming more intense or serious. - Lexico

Escalating (adj): increasing in price, amount, rate, etc - Cambridge English dictionary

Escalate (verb): to become or make something become greater or more serious.

This is what came to mind.

The contest became got harder over time. And so against mounting difficulty the two contestants charged ahead.

You could describe the game as having progressive difficulty.

Gradually advancing in extent; increasing.