Now which one should I start? Maybe glitching?

Glitching
The only glitch I knbew is succubus warp glitch. THis is how it works.
1. Use succubus soul
2. make sure you have cinquedia and use it's special attack
3. attack 3 time(don't do it too quick or else it won't work)
4. use special attack
5. Now you warped into the place that your cinquedia temp-warped you to

WARNING: Don't you ever think this glitch is safe. My whole game memory got resetted after I perform this glitch X.X. It's up to your luck. I don't suggest warping into blunt wall or else you'll end up like me.

Benefit

Using this glitch allow you to go through the switch gates. You can get random stuff(and rare item like julius whip and alucard sword). by warping into the wall of save room. But you may end like screwing all of your save files like me.

getting rare items

Perform the succubus glitch on the save room near the menace room. Make sure you defeated all boss(except menace because you cannot completely destroy him) and obtained all ability soul. If you do. Then do it. Now you flying up the map. Do slide( Down+ B) to move right until you go through the map 2 time. go near your save room(to save walking time) and wait for 5 mins. You'll stop moving. Walk all the way back until your dot reach the save room. You'll appear back in the map. Check your item and save the game. (You can get Chaos ring from doing this by warping through the soul pillar into the chaos ring room)

Defeating boss

I cannot update this until I fnished my game(My game resetted because of malfunction)