Luckily you don't need to add hard tricks to get sub 2! (BTW great job doing the "fast accel" glitch in level 1 :)
Suggestions: -In Level 2, after the second green seesaw jump up to the brown blocks with the coins instead of dropping down. The short slopes tend to slow you down. -In Level 3, jump on top of the brown and yellow blocks (located at 4:47 on the timer in your PB) instead of going down and wall jumping up, this saves a lot of time. It's a bit tricky cause you have to worry about the enemy, but once you've got the timing down make sure to hold down the up arrow when you jump on him and you should be fine (it gives you an extra boost to make it to the next platform)
There's plenty of other harder strategies you can add (like jumping over the plant in level 2), so I recommend watching other people's PB's for more ideas. If you need help with anything else I'll be happy to answer your questions :)
Did you know you can also jump over plant in level 3? It isn't even that hard! Just when you're on top of the slope that's closest to plant, jump and hold and you should grab the stone structure by the plant and climb on top of it, and here it is! (It's not always working).