full scene animations with several frames are indeed resource heavy.
Just use only animations which are as big as needed in size and only for the spots you need.
You're also able to use Lua to move animations or use easing effects (maybe not possible in 3.x)
Easing isn't possible in 3.x. Moving an animation with Lua is possible as is scaling an animation. Tweening isn't possible though as that was added in 4.x & the only way to have an animation transition instead of snap between 2 points would be to use a loop.
@sergey-shapovalov: 2D is very system resource heavy compared to 3D. Animations that are large in both width/height & file size per frame will load very slowly; especially depending on the pc the game is being played on. As Sebastian said, it's better to only create animations at the size you need them to be & position them in the scene manually.
Please see this page
for more information about game optimization.