I've had this for a few weeks.
Use Isobuster on it then ImageBurn.
Plays just purdy on a chipped PS1...
Watch the enemy AI as well, seems much nastier than even Hard mode of retail TM2.
Minion seems a bit weaker as his special doesn't always home properly.
Advance Attacks have completely different button combos.
HH and Axel actually drive OVER you in true monster crush style.
(strangely Axel seems to have the 'Wheels of Death' secret move built in as he can roll over you any time and do fairly high damage (even to Minion).
I've yet to put a lot of time into the game but I will soon. Check out some of the little level changes as well
Nah dude TM2PC HH and Axel can easily drive/run over people, maybe just the CPUs didn't. HH driving over someone completely does like double damage, sometimes uses two specials coined "double crush". Axel ditto, but he doesnt need specials to do it.
EDIT: OH i guess u mean uses a special.