are you talking about the same game? Cause that doesn't sound like this one
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*Face palm* Yea your totally right, I got the two mixed up XD
In order to unlock the animations in this game you need to reach the end of the level with time to spare. If you do that the animation unlocks and can be viewed in the gallery in the main menu.
Its worth noting that the demo cant unlock all animations as only 4 i think, levels can be unlocked and completed.
FYI: There is currently a bug in the game where if you have downloaded and played the demo and then install the full version the levels don't unlock properly. Removing the save file is the only fix for now. There is an update planed to fix that sometime next month.