as other developers said, c2 can handle large layouts max layout size is stacked at 100 000 pixels by 100 000 pixels however above 500 sprite objects moving and updating you may encounter fps drops and high cpu/gpu consumptions which on mobile platforms means large battery consumption and sometimes crashes.. on pc however ... on a newer rig you can run a C2 game with around 15,000 sprite objects at a 24 FPS but since not everyone has its rig updated i wold not place more then 1000 active objects in a layout.
Active meaning ... updating positions changing effects parameters and other stuff.
if they are just static objects(they dont do nothing just stays there as a bg image or hud elements) then you can add around 2500 of them. so you can have usability above all.
this info is based on my personal rig
CPU
Intel(R) Core(TM) i5-6400 CPU 2.70GHz
Maximum speed: 2.00 GHz
Sockets: 1
Cores: 4
Logical processors: 4
Virtualization: Enabled
L1 cache: 256 KB
L2 cache: 1.0 MB
L3 cache: 6.0 MB
Utilization 3%
Speed 0.78 GHz
Up time 8:17:45:30
Processes 54
Threads 798
Handles 25203
Memory
8.0 GB
Speed: 2133 MHz
Slots used: 1 of 4
Form factor: DIMM
Hardware reserved: 47.4 MB
Available 5.4 GB
Cached 1.8 GB
Committed 3.1/9.3 GB
Paged pool 295 MB
Non-paged pool 155 MB
In use 2.6 GB