yes, the new design is where at the time of triggering the bomb would increase the difficulty linearly.
For comparison this is what the original proposal would look like
New version
Here eventually in all cases the difficulty even though it would no longer adjust based on block time would increase to a point of block times becoming unusable on the network.
Thank you to Q (quentinc137) on twitter who helped me walk through the game theory on this.
The last option to explore is if changing the adjustment window is preferable.
e.g Currently the adjustment factor is up if less then 10 seconds, and down if greater than 20. You could increase both of those over a period of blocks, such that the target block time increases after a certain point. I am not sure if this has other complications, but it is worth exploring.