I think the others have said it all. I can see you have made great effort to construct a cage but ideally each hamster would have a larger continuous floor area. It doesn’t look very deep. 45 to 50 cm deep is usually recommended with about 80 to 100cm length. Any additional areas can be good if one area is about 80 x 50. If it is melamine inside that should be ok. I am not sure where the door/entrance is
