I think a general rule of thumb if you want to reach a wide range of devices would be something like:
For mobile games: avoid going over 200mb (going over 100mb will probably still rule out devices with <1GB memory)
For desktop games: avoid going over 400mb (going over 200mb will probably still rule out devices with 256MB VRAM)
Exceeding those amounts will probably make your game only possible to run on high end devices, reducing the number of players who can play your game.
The OS and other applications will still be using VRAM, so to fit your game on a graphics card with 512 MB VRAM alongside the OS and other applications, it's probably best to stay under 400mb.
Consider using Spriter for animations - it's far more memory efficient. Also your screenshot appears to include a lot of redundant images (the blocks/slopes). Construct 2 should deduplicate truly identical images, but consider re-using the same ones if at all possible.