Gee, I've been playing this game far too much. Not that I'm complaining, but I've picked up a few little things that either help with the time or get rid of those pesky enemies that ruin your combo's. These are all for Nero by the way, not Dante.
Scarecrows - Pretty damn easy. If your aiming for more time, as well as not wasting that much time then simply go to the center of the area, jump in the air and snatch all 3 using Enemy Step so that you don't accidentally buster one of them. Have Exceed at the max and activate DT. Use shuffle and just before the attack hit's De-activate DT to further boost the style rank up and get rid of them quickly. This works best for the first three floors. With the large group of them, try to get them in a large group, JC'ing where necessary then snatch a few of towards you, send them into the air with a high roller then use showdown, if your lucky, the rest of the scarecrows will be in striking distance, meaning you can get rid of them quite quickly. If that fails, Charge Shot 3 and Max Exceeded streak are your friends here.
Bianco Angelo - The white one's, not the golden/yellow one's. These are fairly easy as well, you just have to be careful of their sneaky little counters that they like to pull off. Normally what I do, just as they're forming is get a streak in, high roller them and then charge shot them. If they put the shield up, instead of attacking twice on the ground, do one attack on the ground, then jump in the air and use split, they'll counter but you'll re-bound in the air, opening up an oppurtunity to use another split and finish them off there.
Alto Angelo - These guys are annoying, they take more hits to stun and can flip out of combo's. But their is a way around that. DT comes in handy here, land a charge shot 3 on them, then DT, it will send them into the air, just before they hit the ground buster them an de-activate DT whilst firing off phantom swords, this should bring them down to roughly 1/3 of their health, then buster them again to finish them off.
Mephisto - Easy to handle, simply snatch their cloaks or jump into the air so your close enough and buster them, it'll take only two busters then you can slam them into the ground, use split, charge shot 3 and max exceeded streak.
Faust - Pesky bastards yet they can be killed very easily. Same with Mephisto, simply buster their cloaks (It takes about 4 or 5 with Faust) Charge shot 3 them. Wait a couple of seconds just before the explosion, DT and start showdown, if your lucky and 90% of the time it'll work, you'll hit him and easily finish him off.
Assaults - Easy in less numbers, a nuisance in packs. Double Down (Exceeded split.) Streak and Buster are your friend here, wait till they jump out of the ground then immediately streak them (Preferably with 3 exceed gauges.) Then use Double Down and finish them off with a buster (DT the buster if you want more style.)
Frosts - Yeah, these guys. Land in cheap hits when you least expect it. First thing to do is land a charge shot 3 on them, to get rid of about 1/4 - 1/2 of their health, then buster them and whilst they're still on the ground land a few streaks and splits on them. This should be done with just one at a time, otherwise you just risk the chance of one of them hitting you.
Chimera Assaults/Scarecrow - The amount of times I've gone for a good combo and these guys simply stroll in and hack away at you. A simple charge shot 3 will usually finish these guys off, or at least disable the Chimera, then you can streak them with exceed 3.
Chimera Seed - If your after health, these guys will give it to you. If your after style though Exceed 3 and streak is your friend here, for some reason the style gauge will never stop if you continue using exceed 3 streak. (Dunno why.) Land a few charge shots in there just to keep them close together.
Blitz - Don't mess with these at all. Don't use your sword on these, instead as soon as it appears DT and use Maximum bet, twice if possible then land in a charge shot 3, run over to him and buster the hell out of him. Do it twice, three times if possible then charge shot him again to end his annoying, pesky life.
Basilisks - Overall, not that hard but when they come in large packs, that's when it gets a little hectic. The idea is to not use the ground busters, it takes more time and leaves you wide open for attack. Streak them first, preferably exceed 3, then high roller them and buster, land in a charge shot for good measure and repeat.
I can't give you tips on the bosses, as everyone has their own way of doing them. Although I will say this.
Aerial attacks are useful on Berial
Attack the front of Bael to cause more damage.
Double Down, Charge shot 3 and streak on Echidna
Double Down, charge shot 3 and buster for Credo.
Aerial attacks for Agnus, Double Downs and Charge shot 3
Dante - Buster.
Scarecrows - Pretty damn easy. If your aiming for more time, as well as not wasting that much time then simply go to the center of the area, jump in the air and snatch all 3 using Enemy Step so that you don't accidentally buster one of them. Have Exceed at the max and activate DT. Use shuffle and just before the attack hit's De-activate DT to further boost the style rank up and get rid of them quickly. This works best for the first three floors. With the large group of them, try to get them in a large group, JC'ing where necessary then snatch a few of towards you, send them into the air with a high roller then use showdown, if your lucky, the rest of the scarecrows will be in striking distance, meaning you can get rid of them quite quickly. If that fails, Charge Shot 3 and Max Exceeded streak are your friends here.
Bianco Angelo - The white one's, not the golden/yellow one's. These are fairly easy as well, you just have to be careful of their sneaky little counters that they like to pull off. Normally what I do, just as they're forming is get a streak in, high roller them and then charge shot them. If they put the shield up, instead of attacking twice on the ground, do one attack on the ground, then jump in the air and use split, they'll counter but you'll re-bound in the air, opening up an oppurtunity to use another split and finish them off there.
Alto Angelo - These guys are annoying, they take more hits to stun and can flip out of combo's. But their is a way around that. DT comes in handy here, land a charge shot 3 on them, then DT, it will send them into the air, just before they hit the ground buster them an de-activate DT whilst firing off phantom swords, this should bring them down to roughly 1/3 of their health, then buster them again to finish them off.
Mephisto - Easy to handle, simply snatch their cloaks or jump into the air so your close enough and buster them, it'll take only two busters then you can slam them into the ground, use split, charge shot 3 and max exceeded streak.
Faust - Pesky bastards yet they can be killed very easily. Same with Mephisto, simply buster their cloaks (It takes about 4 or 5 with Faust) Charge shot 3 them. Wait a couple of seconds just before the explosion, DT and start showdown, if your lucky and 90% of the time it'll work, you'll hit him and easily finish him off.
Assaults - Easy in less numbers, a nuisance in packs. Double Down (Exceeded split.) Streak and Buster are your friend here, wait till they jump out of the ground then immediately streak them (Preferably with 3 exceed gauges.) Then use Double Down and finish them off with a buster (DT the buster if you want more style.)
Frosts - Yeah, these guys. Land in cheap hits when you least expect it. First thing to do is land a charge shot 3 on them, to get rid of about 1/4 - 1/2 of their health, then buster them and whilst they're still on the ground land a few streaks and splits on them. This should be done with just one at a time, otherwise you just risk the chance of one of them hitting you.
Chimera Assaults/Scarecrow - The amount of times I've gone for a good combo and these guys simply stroll in and hack away at you. A simple charge shot 3 will usually finish these guys off, or at least disable the Chimera, then you can streak them with exceed 3.
Chimera Seed - If your after health, these guys will give it to you. If your after style though Exceed 3 and streak is your friend here, for some reason the style gauge will never stop if you continue using exceed 3 streak. (Dunno why.) Land a few charge shots in there just to keep them close together.
Blitz - Don't mess with these at all. Don't use your sword on these, instead as soon as it appears DT and use Maximum bet, twice if possible then land in a charge shot 3, run over to him and buster the hell out of him. Do it twice, three times if possible then charge shot him again to end his annoying, pesky life.
Basilisks - Overall, not that hard but when they come in large packs, that's when it gets a little hectic. The idea is to not use the ground busters, it takes more time and leaves you wide open for attack. Streak them first, preferably exceed 3, then high roller them and buster, land in a charge shot for good measure and repeat.
I can't give you tips on the bosses, as everyone has their own way of doing them. Although I will say this.
Aerial attacks are useful on Berial
Attack the front of Bael to cause more damage.
Double Down, Charge shot 3 and streak on Echidna
Double Down, charge shot 3 and buster for Credo.
Aerial attacks for Agnus, Double Downs and Charge shot 3
Dante - Buster.