For this round the screen scrolls automatically, so speed is a top priority. If the screen scrolling traps you against a wall you die immediately.
Head to the right, jumping holes and avoiding spikes. Smash the pot and grab the red potion. Now wait. When the screen scrolling is just about to touch you, drop down onto the platform. As soon as you can, jump onto the raised surface to the right. Immediately throw potions onto the blocks at the far right. With luck, the blocks will be gone in time to land back on the platform. Head to the right and again bomb the far right of the blocks. Drop down and head up to the pot to get the key.
For this round the screen scrolls automatically, so speed is a top priority. If the screen scrolling traps you against a wall you die immediately. This is a very difficult round, so finishing it may cost you a few lives. Asterix's version of this round is much easier.
Head to the right, hitting the floating man on the way. When you get to the platform, wait until it is about in the middle of the screen, then drop down onto it. Jump up to the right and quickly smash the blocks out of the way, then jump onto the far right end of the platform and duck immediately (if you don't you'll be knocked off the platform). Ride to the end and continue to the right (ignore the pot). Avoid the spikes and take either route to the right. With the scrolling as far behind you as possible, activate the platform and quickly butt-bash the blocks. Return to the platform and do the same again. Smash the pot for the key, and you are done.