Anti warp is to prevent time warp attacks (HMC started to call it this way). Difficulty is adjusted using maximum allowed time, however it cannot drop below the median time of last N blocks (this is to prevent making mining impossible). Say if target time is 30 seconds and you generate only 30 seconds replays then time will never drop below 30 seconds, if you can genereate 30 second replay each second you can instamine many blocks and difficuly will not increase to counter that. Anti warp adds classical PoW to map generation to prevent this.
Well, I understand now, thank you. I had no time recently for thread re-reading and I had stopped on page 46 for now. So no any HMC special magic here. Just PoW. Actually I had vague understanding of this, but I'm just surprised that the moto game is still pretty human-minable (and map generation is still pretty fast) even with new public bot around, so I began to speculate if there's something more besides just PoW. So far so good. But the price is so low that only few people are bot mining anyway. It would be interesting to look at mining dynamics if MOTO would not be so worthless.
I'm glad that you're still around. Looks like MOTO functions just fine. It's a pretty interesting experiment anyway.
When I read old discussion here, one thought did not leave me. Now it doesn't matter, but anyway. In Bitcoin, to successfully overwrite the entire blockchain, miner's chain should have more work (total difficulty) than the current blockchain. So it's basically more work (and time) consuming and more useless form of 51% attack. But in 'old' pre-PoW MOTO case such miner (as I understand) could just use minimal target for all of his alternative chain. But why it was impossible to use target times as difficulty to prevent such attack? Our attacker just must have smaller target time for his every block compared to corresponding (by number) block in a current chain. Or (more rough variant) he must have smaller sum of target times in his chain (which is the same length).