Thanks a lot for your ideas and sorry for the very late reply.
Actually it is an image sequence from which I made an image sequence. The problem with the image sequence in a sprite is that if I'm correct, these images will be used uncompressed in the code, and thus very very heavy! And there are a lot of them... Around 300 actually, which would make using them as an image sequence in an object impossible.
Well, in subsequent research here, I found out that Sprites with frames are stored & used in compressed png sprite sheets with around 6-9 sprite frames per sheet. So, I think your fears may already be mitigated inherently in Construct.
We are displaying around 30,000 to 90,000 sprites simultaneously on one layout with fully dynamic zoom and pan functionality and Construct has performed well so far under these loads. However, phones do not.
Thanks a lot for your kind words on Healer Quest! The good news is that a PC, Mac and Linux version of Healer Quest is under construction.
You are welcome, and best of skill in your effort.