Not exactly a guide just some tips :)
The requirements for this achievement are pretty tough imo. You need to complete the whole game getting all 5 tears and beat level 8. You will need to have a sub 40 minute time before the ending cutscenes. If you arent already a master speedrunner of this game it will take some practise before you beat the 40 minute mark.
HOWEVER you can just quit and then continue to retry the level you are on (you also keep the same speedrun time as when you first got to the level) if you think you can do it faster. Much better to take your time and don't accept a bad run because every second counts when you make it to the end. Note* remember to carefully select 'continue' after you quit a failed run. Selecting new game by accident means you will instantly lose your saved progress.
Right off the bat I'd strongly advise using holy fire grenade on the first two levels as it's the most powerful weapon and can help make fast work of practically any mini boss (except pandemonium) and end of level bosses. It's massively helpful for killing the 2nd level boss! If you die at any point during first two levels then I'd highly advise restarting. You can also kill the vulture mini boss very quick with holy fire, saves like 20 seconds. After the boss quickly make your way up the bubble/yellow bird area asap, collect double jump as it's much faster for this section and the next provided you can formulate a safe and quick strat what works for you ps always go as fast as possible.
Holy fire grenade is quite an awkward weapon to master but it is very powerful. It really pays to make it to the end of level boss (except moura who's second form is strong against holy fire) carrying this weapon, because of the destructive power it saves valuable time in boss fights. It helps a lot to memorise enemy locations. Personally I used the crouching holy fire attack to tackle most normal enemies.
Imo you basically need to thrash the nuts out of every level and using every trick you can muster ( knowing all the invincible power up locations is useful as you can just run through the enemies/traps etc for about 30 seconds ).
Unless you die in an area where you can start your next life immediately. The chances are pretty slim of you breaking 40 minutes.
Make good use of double jump in places and learn where you need to collect some time from certain boxes.
I had 33 minutes exactly going into level 8 which just about made this doable for me, only just scraping through after 5/6 attempts and finished like 10 seconds under the 40 minutes.
I'm not able to post any video's but copying some speedrun strats from YouTube videos is very handy.