Not a very fun game. I'll summarise what I found to be important things to make note of:
Simple gameplay. I think the potion mechanic was executed quite well, especially during the last few levels.
Good for a short game. The level lengths are just right for people who don't have much time to play a game. The game shouldn't take longer than a couple or so minutes to finish.
There's too much backtracking. This got annoying really quick. I think it adds artificial difficulty to the game and it's not really very fun to backtrack, especially when you already know how to finish the a level from the onset. Level 19 was probably the greatest abuser of this backtracking mechanic. The level went something like this:
1. Get the yellow potion,
2. Jump to the other side making sure to avoid the purple potion,
3. Wait for the moving platforms so you can go up then right to that walled up spot with a button and a gate.
4. Press the button to activate a platform down below,
5. Go back down and jump to the starting side to get the purple potion,
6. Jump back to the other side and wait for the activated platform to take you up because you can't jump high enough,
7. Run under the moving spikes and don't get hit,
8. On the other side of the spikes, take a platform that takes you up.
9. Jump onto the platform with black bricks
10. Step on the button to open up a gate.
11. Go back down,
11. Go through the moving spikes again but this time from right to left instead of from left to right,
13. Jump back to the beginning side,
14. Repeat steps 1-3
15. Go down.
16. Jump off the platform to get the key and jump back to the platform just in time to avoid the spikes.
17. Go back up to that platform with the gate and the wall in it.
18. Jump back to the place where you started
19. Unlock the locked gate
20. Go through the door behind it to finish the level.
If that's your idea of fun, I don't know what fun is.
Sometimes the potions were placed in stupid spots. Personally, I didn't encounter much of a problem with accidentally stepping on potions, but I could have, and anyone could have regardless of skill level. Do you think it makes the game more difficult if you place some potion in a place that would force a player to reset if they accidentally stepped on them? That's not good game design.
Advertisements after every level. I guess since this game has gained some popularity you think it's appropriate to monetize it by placing an ad. I don't mind ads in the beginning but having ads after every level is really not something anyone wants to see.
Unseeable spikes. This one's kind of unfair mostly for the first time it appears, you kind of just expect spikes to be there in the following levels. You should add a function for the down key so players can look down and check for spikes. A lot of games have that, and it shouldn't be too hard to program.
None of the levels were really challenging. Sure they were challenging but through artificial means, like the things I've mentioned above. Technically none of the puzzles were too complicated, and they were all fairly easy to figure out.
Overall, this game has some potential but it's really not a good puzzle platformer. I just wish your level designs weren't as gimmicky as they are.