Those last two VVVVVV rewards are surprisingly easy if you use the game's "Invincibility" mode and unlock the time trials and secret lab from "Game Options" -> "Unlock Play Modes" (normally I think they'd unlock by beating the game and collecting trinkets). The £0.10 reward is actually the most time consuming since it requires you to beat the game.
Super Gravitron: 30 seconds - Go to the secret lab, find the teleporter square, and survive for 30 seconds. You can do this with invincibility on if it proves to be too challenging (I only made it to about 20 seconds without it).
Laboratory Mastered - This achievement is actually glitched but in our favor. Seems like you can get any ranking on the Laboratory time trial and still unlock the achievement after reaching the end. I got a "B" ranking myself and it unlocked instantly.
- Dr Sasquatch, Tsel, indef and 3 others like this