Thank you both, Pedro and ThatScar, for the comments.
@Pedro
It is not a problem that players discover X beofre it is needed, and the 4 early levels do not get that much easier with it, so I skiped the work of preventing players from using action before level 5.
Since we only talk about "press x" once, if a player skips it, the game will not be possible to finish. Thus I put in the discrete reminder in the level. I think it is discrete enough that it shouldn't retract any from the experience in general.
The double camel is a "known feature"... It can appear on multiple levels, and I don't think that it matters that much. If there was an easy fix for it then I would implement it, but the only good way I could think of is to, in some way, order the goals and then add camels in the order they were ordered in case of same time camels, but it feels like too much work for something which is really not that big of a deal.
Thank you for the graphics suggestions. Indeed it is very subjective, but I find this to be a hard thing to even get an opinion about, so others subjective input is nice. The background sugestion is great, I will implement this.The water is actually animated... but they seem to all use the same texture, so you cant see the animation, thanks for pointing this obvious fact out.
@ThatScar
Your comments regarding "up to level 10" agrees with what Hand-E-Food writes about the early levels being "Samey". I will take this with me for the future. It is interesting that you solved level 19 and 20 faster than 16 and 17. Indeed 16 and 17 are introducing some new concepts/patterns but I still find 20 so much harder.