cs-tween VS flux

Get them from Robert Penner's easing site instead. Or, even better, use the normalized ones from flux.lua since they're easier to work with and understand. You can pass them to any lerp function to blend vectors and colours too. You can use this generator to create versions for your language of choice or use these C# versions.

You can make something slide onscreen and scale up; and then half a second later scale down. Coroutines make it easy to write code to do those things in sequence. Find UI animation that's written as code instead of in the Unity Inspector easier to understand and debug.

A "custom tween engine" isn't that big an ordeal, but making something with all the features of dotween certainly would be.

cs-tween for C#

Concratz on the game, Flux also has tweening it might do what you descibed above: https://github.com/rxi/flux

Perhaps a bit off topic but certainly a useful library when trying to do some specific movement of objects: https://github.com/rxi/flux/

Flux for Lua (visualization)

flux is a tweening library for Lua. It's great, but sometimes it's hard to guess what the curves will look like.

I find the libraries by rxi (like flux) are pretty great. How have you discovered yours? Searching GitHub, using love2d-awesome, love2d forums?